Jules--
Sadly, this sounds so much like my own difficult child, and we STILL haven't figured out how to be nice to friends so that they "stay"...
Counselors used to spend a lot of time with difficult child doing exactly as Marg suggested and "role-play" different scenarios. Unfortunately, in real life, the other kids didn't always behave exactly as we had practiced.
And difficult child seemed to have trouble understanding that people can be friends with difficult child and somebody else at the same time. So that was also a concept we tried to practice...
I feel for you. It's probably best to just set up some very short play dates under very controlled circumstances...As in, have a friend over to watch a movie. When the movie is over, the friend goes home.
