I am having the same issue with my 3 year old as well. The childlife specialist at our CF center recommended making him a book about things that brothers can do when sisters are sick, in the hospital or getting treatments. It has really helped. I also give my son Tums just a half of one in the morning and then a vitamin at night so he gets medicine too. Our PCP suggested the Tums because most kids do not get enough calcium. My son love to pick his color.