[muffinman26]

Have you modeled to them how to make and develop friendships? Have you tried asking them what they've tried to do to make friends?

Limiting negative stimuli isn't enough for people to automatically replace it with good stimuli. It's the same struggle as leaving an abusive relationship or toxic job. People can know something is bad, but they're much less likely to leave a bad situation if they can't imagine what the better alternative is.

For example, my Dad is terrible at making friends. His co-workers and acquaintances like him, but most of the time his only significant relationship is with his spouse and his kids. My mom was great at making friends and finding community, but her ways of relating to people seemed inaccessible and indecipherable to me as a guy.

I did and do go to clubs of various sorts, but it's a real struggle to figure out how to turn those casual acquaintances into meaningful, reciprocal friendships. As soon as I had my own struggles or wasn't obsessively invested in the club, those friendships vanished overnight. I don't know any good books or resources to learn the skill of making friends. I can definitely see how someone who had more mental health struggles or was less extroverted than I who struggled to make friends in these situations would give up on trying.