Manny doesnt care about his friends, his comfort or anything that doesnt involve money. He would go play for any team in any league if they offered top dollar. If it were a japanese league, he would go to Japan. His friendships/loyalties etc mean nothing to him.
That being said, he isnt going to be on the Yank's next year because they arent going to waste the money. They have seen first hand how good he can be, but also how destructive and how selfish he is. They are going to be spending their cash on pitching, they are set on offense.