I totally agree with you. Kids grow out of this phase. So, its fine to ask about his "friends" and what not. But, what you don't want to do is distort his sense of reality. Buying gifts for the friends could be doing just that and, if dad really is doing that as if it is all a big joke, then that's worse. That is just hurtful - even if your son doesn't get it. If your son doesn't get to interact with other kids then his imaginary friends may be his way of letting you all know that he NEEDS friends (he'll get them one way or another). I didn't go to preschool and I became a doctor, so no, not all kids need to go. But my little sister went. She loved it and still has fond memories. My mother felt she needed more than I did. You are right - being fair to each child is being attuned to each of their needs, not necessarily treating them exactly equal. Maybe at least you and or grandma could set up playdates. Good luck with this.