Autism

[Jazzy G]

If there's a Games Workshop/Warhammer shop or whatever they call themself nowadays, or similar hobby shop nearby see whether there are events run there. If he's worried about the other people there at first offer to go with him until he finds his feet, which probably won't take long in a place like that. I know I've made some great new friends at my local Geek Retreat. There may also be Autistic/neurodiverse social or self advocacy groups that have meet-ups. I met Vicky through one of them. 

As for your weed question, I think weed affects everybody a bit differently on account that everybody is different.

Hopefully he starts to feel more comfortable in himself, as in my personal experience I found that I struggle a lot less now I don't have as much masking to do around people. I'm still getting the hang of it, as I was diagnosed late, but I'm definitely a lot kinder to myself now than I used to be.

As for the accommodations you're making around him like eye contact, and not teasing him as much it sounds to me like you're doing great. Just keep being there.