This is my exact opinion. It's just wrong. I will be too embarrassed to attend when my other siblings AND their children (with spouses barely known to the bride) are invited. I will feel like the family peon. My niece does not see those cousins either. If it weren't for the fact that he is the only one left out it would be different. My oldest daughter was not invited for obvious reasons. She is fine with it. She could not go anyway.
I think they are going to twist it around to look like I told her not to invite him because I may have said they probably could not come. (it will be an easy $1,000 for hotel, food, etc) Either way, something bad is going to come of this and I really don't need anything else to hurt me right now. Not to sound too selfish.