DS age 5 and DD2 age 3, love playing together chasing each other, rolling around on the floor etc. DS will seek DD2 out to play with over DD1. They do fight, over toys mostly, as well though. But, although DD2 loves DS he says he doesn't like her and won't do things like hold her hand or sit next to her at the table or on the couch. He even asked a while ago "when will DD2 die?"
DS is 17 months older than DD2 and he has a big sister who is 16 months older than him. He loves his big sister, as does DD2, and will happily sit next to her, give her a cuddle etc.
What can I do to make him love her, or at least like her?