I think they'll be closer friends. Remember when Derek told Christina that he would have never chose her as a friend but she was like family now.. Meredith's"Twisted Sister".
You people are crazy. They don´t even LIKE each other, they are in each other lifes because of Mer. That´s the only thing they have in commom. Der is helping Cris because he feels guilty, like it´s his fault that she is "ruined". And he´s doing it for Mer, because right now, she doesn´t have that commom ground with Cris, he has,,,
They are not. Just not. It's not even worth elaborating 'cause the idea itself is ridiculous.