xyzCherry,
Another idea here if you want to try it......this GM goes Mitzi not wanted at the boy functions so....... what about trying calling this GM and telling her that you and Mitzi are going to a girl function and would like to invite her. Really what does a five year old really care about a boy or girl function and what really are boy or girl functions? Gosh I went to the Circus and the Ice Capades w/ my Dad plus baseball games - the most important part was that I was with my Dad.
Is might be scared to have her around...get close because she doesn’t want anything to happen. Here her own daughter passed then Mitzi has a condiiton that may cause heartbreak also.