A/N: I was planning to add this as one of my ficlets but, I thought it was too long so, I decided to make it as a one-shot instead. This is inspired by a post in Tumblr. This is an AU where the Winchesters are hunters and Mary is alive.
Hope you will like it and sorry for the errors.

Scarlet Letters

Bloomington, Illinois
February 10
~x~x~x~x~x~x~x~x~x~x~x~x~

"A letter for John Winchester!"

The mailman repeated the same words twice while knocking on the door of the motel room John Winchester is currently staying at. John, who was busy writing something down on his journal, immediately went for the door and got the letter. After thanking the mailman, he sat back on his desk with the envelop on his hand. He examined the back and was surprised upon seeing what was written on that paper.

"A letter from Mary?" At first, he looked confused but he slowly smiled. What kind of husband wouldn't be so happy to receive a letter from his wife? But, he wouldn't be so sure on what's written for Mary might be angry at him. He took out the two pieces of folded paper and slowly unfolded them both. He was, however, surprised upon seeing the slightly small words and the long paragraphs. It indicated that something important must have happened that Mary decided to tell him. He then, started to read the letter.

Dear John,
How was everything going along with the hunt? I still haven't got much work yet but, I received one of the best and loveliest news I've ever heard. Although at first, I wasn't sure about telling to to you because, I believe you wouldn't like it or even approve it but, I decided to tell you anyway.

It's about our son, Dean. Some time before dinner last night, he arrived home with a stranger. At first, I suspected him as a disguised informant who wants to know more about us. But, I was wrong when Dean introduced the man to me. You wouldn't believe what he said about the man's identity. It was the angel, Castiel who came down to Earth to visit us and, specifically, Dean. Of course, I was surprised but, I didn't believe Dean at first for, I wasn't really sure if his companion was really an angel. Because of that, Castiel showed me the shadows of his wings so, I finally believed in him. I then, welcomed them into our home.

I let the boys sat down on the sofa as I went straight back to the dining room to start preparing the table for our dinner. From there, I could hear them having a conversation about a hunt or something. Whatever it was, I didn't mind that soon after and continued preparing. As soon as I was done, I called them and Sammy who was busy with his research upstairs.

Since angels don't really eat, Castiel just sat with us in the dining room. It felt uncomfortable at first because, he seemed to be watching us but, we got used to it as time passed by. We talked about Castiel who is said to have some sort of trouble of understanding our ways but, he said that he will soon get used to it.

During this conversation, I can't help but notice Dean and Castiel secretly glancing and looking at each other sometimes. It was no ordinary look for me because, it looked like they were longing for each other. So, it bothered me. And then, the idea that our son, Dean, might be in-love with this angel struck into my mind.

It does sound surprising from the thought that Dean is in-love with an angel that is possessing a male vessel. Dean isn't homosexual or bisexual but, it was really the first time. That night, after dinner, I talked to him privately in his room and asked him directly. "Are you in-love with Castiel, Dean?"

He couldn't answer me properly but, I saw his face flushed red. With a gulp, he answered. "Yes."

You wound't imagine how shocked I was that I nearly screamed at the top of my voice. However, I prevented myself from doing so because, I might disturb Sam from the next room.

"I know, it sounds surprising," Dean said. "But, seriously, at first, I had no feelings for this guy but, as time passed by, things happened and all and I just...found myself loving this guy."

"Why, that sounds interesting," was all I could say. Our son really likes this angel. So, I decided to give it some thought. If Dean truly loves Castiel and he promised that he will love no one else but him, as mother, I have to support my son with all my heart but, I also have the will not to. However, I do understand Dean. So, I just extended my arms and gave him a hug. "I wish you luck on that, sweetie."

He simply hugged me back and thanked me.

This morning, they already left to continue their hunt which brings me to the moment I am writing this letter to you, John. Whatever your thoughts may be on the relationship of our son and his future with his possible future husband and our future son-in-law, I will accept them even if it is against our will.

Always loving,
Mary

John was left wide-eyed and had mixed emotions after reading the two-paged letter. He started to give deep thought about the subject. As a father and the head of the family, he should also decide about his son's future and finding out that his own son is in-love with a man-and not just any man, an angel-is truly surprising. He didn't seem to approve it at first but, from recalling what Mary narrated, it really seemed that Dean truly loves this Castiel. Finally, after a few moments, he ripped a blank page from his journal and took out his pen. He then, wrote:

Mary,
I've received your letter. Upon Dean's arrival tonight or whenever it may be, tell him about the letter you've sent to me. And also, tell him to do what he wants but, he will be to blame if something bad happens to their relationship.
- John