What your SIL said really hurts - especially if she knew your own health situation. As for your doctor, I am really ticked with how he handled what may have been a valid concern. My doc and pdocs all work together. I just wish everyone's were on the same damn page.
I'm sure we've all sat there fuming at times when people mention and discuss mental health as a joke or in negative terms. Even worse when they have been disclosed to about our health. My brother is really bad for it which really concerns me. Not only am I bipolar but his step daughter is psychizophrenic.