Last time Mary saw Dean, he was just a little taller than her knee (or so it felt), obnoxiously (and adorably) hyperenergetic, and wanted nothing more than to be just like John, despite how obviously he took after Mary (much to John's amusement).
When Mary came back and met her son again, this time all grown-up, things had significantly (read: alarmingly) changed. Dean was taller and broader than her (and Sammy even more so), his energy contained in a grimly muted atmosphere he carried around with him (along with the weight of the world on his shoulders), and (from what she had learned) really had turned out like John, but not the loving, doting John that she knew.
No. If she saw John again in the afterlife, she was going to fucking murder him.
She found it easier to talk to Sam sometimes. He hadn't even started talking when she died; she didn't have previous ideas to compare him to like she did Dean. She liked Sam, and she liked to think he was a lot like her and not at all like his father. He was smart and patient, caring and overly kind, though not to the point of naivety. She never could have imagined the little boy she had held once turning into such a great man. That was one of the better things about returning.
Dean was difficult. She kept thinking back to how he talked when he was little and followed her around the house while she now followed him around the bunker. They struggled emotionally; Dean especially, Mary thought to herself. They didn't do a whole of 'catching up'. Mary let that be. She could let him take his time opening back up.
But honestly, when was he going to tell her he was married?
The angel was… okay. Mary didn't particularly like him almost solely on the fact he was with her son. She couldn't just go from thinking of Dean as a little kid to a wholly and truly grown up adult with a life of his own and a marriage and a place to live.
She really, really hated hunts, especially now. Especially when Castiel went with them.
They found themselves trapped in a haunted house with a vengeful spirit, once. Mary had been thrilled to be invited by Sam and Dean, until Dean said (while texting in the car with his other hand on the wheel; how did John raise these boys?) "Castiel is going to meet us there." Of course he was. Mary wasn't even surprised enough to roll her eyes in exasperation at this point.
Castiel did meet them there, outside a decrepit old farmhouse with walls so stained by soot from an old fire that it looked black. He wore his trench-coat over his button-up shirt. Who dressed for a hunt like that? What if one of his buttons snagged on something and Dean ran back to get him and they both died? Because Dean would definitely do that.
Dean immediately departed from Mary and Sam to converse privately with Castiel, over what Sam told her was a "private" and "different" matter than the one that had brought them to the house. Lover's quarrel? Mary thought. They didn't seem to be fighting, not with how close they stood to each other, but their expressions were serious. Dean moved his hands in an emotional gesture, and Castiel just shook his head in response. Dean looked away, saw Mary and Sam, and walked back over to them.
They laid out a simple plan to search the house – split into groups of two and cover more ground. Mary was, of course, paired with Sam. He smiled kindly at her in response, and Mary returned it before glancing over to look at Dean and Castiel. Castiel was studying the house with a pensive gaze, while Dean looked right at the side of his head like it contained a key to the whole investigation.
Mary and Sam took care of the ghost. They met up with Dean and Castiel about fifteen minutes later at the car.
"Where were you two?" Mary asked, turning to face them in the back seat. Dean attempted to give her a charming smile and Castiel's head tilted a bit.
"The barn," said Castiel.
"The barn," Mary echoed. "We never agreed to search the barn."
She saw Sam's mouth press into a thin line. He didn't turn his head to look his brother.
"Ah, well, er – Cas and I," said Dean, "we figured you and Sammy could search the house, and me and Cas would go check the barn."
"The ghost didn't live in the barn, Dean."
He spread his hands in a placating gesture. "We know that now."
Mary turned around to face the road and cranked the car. As she put it in drive, she said, "Dean, your shirt is buttoned wrong."
Dinners were unbearable. Yes, they were family meals, but Castiel was part of the family now too, so it wasn't as if Mary just had time to reconnect with her now-grown-up sons. At least he was quiet, she thought, as she picked at her plate. But all Dean's attention inevitably went to Castiel. They had a pattern for dinner conversations now: Mary would ask a question, Sam would respond in earnest with a long explanation, Dean would chip in every now and then, and always turn to Castiel to see how he reacted.
On one hand, Mary thought it was cute and sweet. They had to be in love. Dean probably didn't even realize he was doing it, or smiling a little every time he glanced Castiel's way. It was those little things that told her they were something serious, not a simple crush or a short fling. She had looked at John like that, once. She had seen the world in him. (That was, of course, before he destroyed her little boys' worlds.)
She asked Sam later one evening, after Castiel and Dean had retired to bed roughly five minutes apart, "Does he love him?"
Sam didn't question her seeing it, and he didn't question who she meant. He simply said, "Yes."
"Dean loves Castiel or Castiel loves Dean?"
Sam just repeated, "Yes."
One part of Mary went to bed frowning, discontent, and ill at ease. Her baby boy wasn't supposed to be grown up. He wasn't supposed to have a spouse and a bunker and a job. On the other hand, her baby boy was happy. A little broken, but put back together.
She didn't really begin to accept it until one late-night conversation with Sam later.
"He was broken, Mom," he said, when discussing the aftermath following John's death. "It was like he had lost everything. I didn't know what to do."
She said, "I wish I could have been there for you."
But Sam just shook his head and said, "He was broken down to his core and Hell just made it turn from a scratch into a canyon. I didn't think anything could fix it. I didn't think I would see him happy again. I didn't think that was possible, with our life."
Mary sensed the "but".
"But then he found Cas," Sam said. "He didn't… get better. Not right after meeting him. Cas wasn't some magical fix-it. But it was like Cas… stitched him back together. He started smiling more."
Mary still had her doubts and her fears and her misgivings about Castiel, but then, because of Castiel, she had Dean.
Mary asked Dean at breakfast, while sipping a cup of lukewarm coffee and facing down at a yellowed book page, "Will I get to walk you down the aisle at some point, or did I miss out on that too?"
Dean choked on his eggs. Castiel's head tilted to the side. Honestly, he was like a giant puppy. Mary didn't love him like Dean did, or accept his presence quite as well as Sam had (yet), but she could see why they loved him so much. That was enough for her. It had to be.
"You – I'm not – Cas?" Dean said.
"Yes?" Castiel asked.
"Yes," Mary said.
Dean spluttered something else unintelligible. Sam translated, "They're not married."
Mary heard it: yet.
She put her cup of coffee down on the table beside her book and looked at Dean. "I expect to be given ultimate control over the planning. Sam is too biased and you and Castiel aren't allowed. That leaves me full rights."
"Mom – it's not – we –"
She looked at Sam. "What about a summer wedding? What do you think?"
Sam shook his head. "Too hot. What about fall?"
Mary smiled at him. "That sounds wonderful, dear."
"Cas and I aren't engaged!" Dean said. "You can't start planning our wedding if we aren't engaged yet!"
Yet.
"Castiel," Mary said, turning to face the angel, "are you and Dean engaged?"
She saw Castiel's mind whirling. He said, "Yes, ma'am."
"Cas!" Dean exclaimed.
"I'm sorry, Dean. Your mother is quite intimidating."
She leaned back in her chair. "Wonderful. So I can get right to work today. Sam, you'll help me, won't you?"
Sam said, "I already have a file dedicated to it on my computer."
"Sam!" Dean snapped.
"That's great, dear," Mary said. She stood up, picking up her almost-empty mug as she did and closing her book. "I think I'm going to go put this up. When I get back, Sam, you and I can start discussing tux styles."
"But it's our tuxes!" said Dean.
Mary just walked out of the room, leaving Dean and Castiel in a mutual shocked silence. It didn't last but about five seconds, and then she heard Dean turn on Sam.
"Wait, why did she think I'm gonna get walked down the aisle? Why does everyone think I'm gonna walk down the aisle?"
"Dean, I will be happy to carry you down the aisle if you do not want to walk."
"…thanks, Cas."