Digging the grave kept Sam from going over the edge. Digging made him feel like he was on a simple salt and burn job. Digging released some of Sam's anger and put it into something productive. Sam dug with a fury and speed that was simply unheard of. His right wrist still twinged when he dug a grave, and his back had hurt him since Jake had plunged the knife into it and since then Dean did the heavy lifting. There was no Dean to do the heavy lifting anymore. Sam was no longer a little brother in need of his older brother's assistance, he was a grown man, a man who had to do things alone from now on, had to be independent and take care of himself. This was his first act as an independent man. So Sam was pushing through the pain. He was even grateful for the pain because it acted as a reminder of what his brother was suffering through right now. It was only a fraction, an infinitesimal fraction, of the pain and suffering his brother was enduring, and for that simple reason Sam pushed on, pushed through the pain, past the tears, past everything. He would do this for Dean. He owed Dean so much and this was only the beginning of Sam's repayment. Sam had a lot of work ahead of him, and this was only the beginning.
Bobby and Sam lowered the box containing its precious cargo into the ground and Bobby glanced at Sam to see if there were words to be said. There weren't. Sam simply picked the shovel back up and began spreading the earth on top of the box that was simple, crude, and lacking in ornamentation and polish.
Back at the house it had taken Sam over three hours to prepare himself to put his brother in the coffin and another hour to work up the nerve to put him in the back of Bobby's truck, secured with bungee cords instead of seat belts. Sam's hand shook when he got into the Impala and began the long drive to Illinois.
Bobby asked why Sam chose that spot, and why not somewhere on his back forty. Sam didn't want to tell Bobby that he intended to be doing some serious mojo to get his brother back, and he didn't want Bobby's house to be ground zero if the price was Sam's soul. He didn't want Bobby to be killed because the demons sent him on a mission to kill hunters. He wanted Bobby to have enough time to hear about it and be able to get away when the shit hit the fan.
Both lost in their thoughts, the two men stood beside the grave, each wondering if there were words to be said, if there were any words to be said. Dean was so many things to both of them, and Dean never realized he was worth any more than a weapon might be. Sam regretted never telling him just how important he had been in his life, and even while at Stanford he had missed his big brother. Bobby regretted never telling Dean he loved him, regretted never telling him that if he had had a child of his own he would have wanted that child to be exactly like Dean; selfless, loving, caring, and above all able to make a terrible situation bearable.
Sam was the first to turn away from the grave, the first to get into the car and drive away. Bobby knew that Sam wasn't going to be going back to his house, knew that he didn't want Bobby to follow him. Sam wanted to be alone, and no amount of pleading, yelling, and threatening was going to change that fact. Sam was the lone Winchester standing, and when Winchesters were alone, they liked to lick their wounds in silence. It was a trait both had learned from their Daddy and there was no way that Bobby Singer was going to be able to change that now.
"Dean, I'm so sorry son." He said as he heard the Impala growl away. "I'm so sorry for so many things."