Autistic woman in her 40s here… (diagnosed, in case that matters). This therapist sounds odd to me, and I would take her advice with a pinch of salt, however well-meaning she might be.
Honestly, your ‘neurotribe’ just amounts to ‘people you feel relaxed and happy around’ - brain wiring is no guarantee that you will get along with someone, because autistic/ADHD/neurodivergent people are as individual as anyone. You have to build a friendship the old fashioned way. I’ve found neurodivergent people I instantly click with, and others I find really annoying… just like I have amongst the neurotypical people I meet.
I will say that us weirdos tend to gravitate towards each other in social settings, usually because we’re floating around the edges feeling mildly uncomfortable… the school parents I’ve become chatty with over time definitely share a certain ‘something’ and I’ve been totally unsurprised to discover that many are also neurodivergent (mostly ADHD). It was the same in baby and toddler groups once upon a time.
We don’t all go around announcing it up front, but people send out subtle signals in the way they behave, whether they mean to or not. Even if I don’t realise it at the time, it’s usually the reason I feel comfortable around some people when I may not around others.
In terms of deliberately seeking fellow oddballs in the world, look for the people who also seem uncomfortable in the groups you’re in. Also the adults sitting on the floor when everyone else is standing 😆 Take up niche/nerdy hobbies (or anything that requires a certain amount of geeky focus…) - crafts, choirs, performance, circus skills, book groups, gaming... there are loads of us out there in the world, just going about our business along with everyone else!
You’ll also find dedicated ND meet-up groups in lots of areas, but that’s never really been my thing as it feels too intense for me. It’s just not that big a part of my identity, and I wouldn’t want to artificially limit who I meet to just one ‘tribe’.
sorry - mini essay there!!