Wow. I would be really annoyed too.
Especially if they were so willing to get rid of their family dog and then soon after buy not just one, but TWO other dogs.
Doesn't make sense to me...
Maye you could suggest some dog training for your parents' dogs? You could do this in a friendly way without coming off mean. But if you're like me, you don't like leaving your furbaby alone, then I would feel that either your parents are going to have to start training their dogs or you just won't go over anymore!