My son is 8 and his sister is 4. He has no interest in playing with her. It really gets me down, I try to get himto play with her, even for a few minutes and he wont. Any advice? My 4 year old would do anything with him - she is very easy, not fussy, would enjoy 5 minutes of a game or drawing - anything - but he is a stubborn boy and for the most part ignores her.