Dean was way too young to remember their first meeting, but Cas - who was almost ten back then - remembers it perfectly. It was the first time when he saw a baby that was not a wolf- such tiny, warm, sweet smelling creature that smiled at everything, including Cas. Castiel’s father put his hand on the shoulder and told him that leading a pack means not only taking care of the wolves living in it. And then Mrs. Winchester let him hold little Dean for a while, and Cas was fascinated with his curiosity and complete lack of fear.
He never thought he will meet Dean almost 22 years later, though.
When Dad was hunting a monster up around Massachusetts, he’d drop his boys off at Donni’s - oops, Ms. Donni’s - parent’s house to be babysat. After all, at merely two, Sammy was too young for a six-year-old Dean to care for for very long, so they needed a caretaker that could be trusted. Dad had saved Ms. Donni’s family a couple years back and so was happy to care for the two. She was so patient and good with them, not minding that Dean still didn’t talk much to anyone except for little baby Sam and, occasionally, Dad - and even then, only in private. She understood that he’d been through a lot.That’s why Dean liked Donni. Even if she did make them eat green food.