My 25 yr old ds has level 2 autism with a borderline learning disability. He went to mainstream school but had a lot of input from speech and language, OT, paediatrics etc.
He didn't actually get his autism diagnosis til he was 13 - it just was not obvious that autism was his primary diagnosis when he was younger because it seemed to present as a global delay. He was very slow with speech and language but also very slow motor skills too.
His diagnosis opened up a world of support and was the best thing ever for him because, in our local town, there is a support organisation specifically for youngsters with asd diagnosis.
When he went there he definitely found his people. All levels of severity - some non verbal, others very verbal - but ds fitted right in.
In fact, after his first visit he said "Mum, they are all like me!"
From that group (he did have to attend mainstream high too btw) he got into supported employment. He works at a cafe that provides employment opportunities for disabled people. He loves it and has been there since he was 16.
Unfortunately, we had bad news on the housing situation for him. In our area, supported housing is only allocated to those with night needs (and i think that means only those that need someone in to give medication at night) So he does not qualify. He will need to live at home for the foreseeable.
We have a legal guardianship over him as he cannot manage banking, dealing with important letters, medical issues etc.
Honestly though, he is the happiest lad with no mental health issues as his life is very structured and manageable for him.
I have other children cognitively able and ND, and they have struggled far more as expectations are higher for them and they have not had the support.
I understand your concerns as, when my boy was small and so behind, i would have given anything to peep into a crystal ball and glimpse the future.
It's better than i could have ever hoped - my ds is verbal, can catch a (known) bus independently, he has an activity to do 6 days every week (he does 3 voluntary jobs and lots of social activities)
He does dress himself and take care of his own personal hygiene (sort of!)
He is totally loveable, funny and a really popular member of our family.
If we took his familiar supports away, he'd shut down and become very stressed. But he actually is pretty independent within this predictable weekly structure.
And, although he qualifies for full pip, he gives to the community through his voluntary work. He is cheery and people know and love him around our town.