Sounds like MIL needs some sensitivity training! My parents are like that and it drives me nuts. My mom probably woudn't mistake a mental health disorder with mental retardation, but my dad sure would. I can't stand to be around him sometimes just because of all the crap that he constantly blurts out. One of his favorites is "you're a reject from the retard factory," and he used to say that to us kids all the time. That sure doesn't feel good to hear as a kid, but as an adult it's just disgusting.