"What happened last night, Cass? I am really sorry if I freaked you out; it was not my intention. I was trying to comfort you," Dean said in a concerned voice. He really didn't mean any harm when he hugged him. Castiel knew this, but he certainly didn't want to complicate things further than they were.
"I understand, but that's not of importance; now stop it," that's all Cass said before he sent Dean back into the past. Dean woke up on a bench and then headed to the diner near him. He ordered coffee, and next to him was a guy reading a newspaper who happened to be the younger version of his father. Dean trailed him till he saw his mother; they looked happy together. For once, he didn't completely dislike the angel, and this experience could certainly make up for Castiel running out on him.
But as he enjoyed the sense, a demon showed up and attacked them, critically injuring his father. Then his mother did the most unthinkable thing; she made a deal with the demon to spare his father's life. The demon asked for one thing: on a certain day in the future, he would be welcomed into her house. His mother agreed to those terms. When Dean heard which date, he felt his legs go weak—the day he would never forget. That was the day his mother died.
"Stop, don't! I am your son, Dean Winchester. That's the day you die, Mom, don't please." Dean didn't even recognize his own voice. His mother only looked at him and still agreed to it. "Why?" Dean asked in a broken voice. "We lose you; I lose you, why?" He was now in tears. "Because I love him, and that deal gives me more than a goodbye with him. It gives me a life with him. I'll take what I can get, Dean," his mom answered. "How are you not spooked that I am from the future or much less your son?" Dean asked, trying to distract himself from what he just witnessed or the very many questions he desperately needed answers to.