First off, just a quick comment, I don't want to laugh at your pain, so don't be offended, but I burst out laughing at nr 1! I'm the weirdo in the family too and just to imagine their faces and glances!!!!

People who self-harm aren't mental at all, and yes, it is very insensitive to say that. As I see it, it's just an unhealthy way of expressing emotion, like smoking is an unhealthy way of relieving stress. Bad habit...

You were right not to argue with them, people like that have a very distorted view of the world. Maybe your sister's bf is very insecure about himself and puts others down to make himself feel superior? I have find that some people just go through life and think that anything abnormal is classified as "mental" IMO, these people are the mental ones! But sadly you cannot change their views of life by arguing, you can only hope that... (ok let's not hope for that!)

I know how frustrating it is to be in the company of people who refuse to try and understand other people. They think they are always right and that the rest of the world is wrong...