I have two with ASD, diagnosed at 4 and 6, within 2 months of each other. We knew nothing about autism, and were completely devastated.
Not helped by the professionals involved sadly, the only language they spoke was negative. I suppose it must come with the territory. We went down the rabbit hole of multiple worthy therapies, all of which looked good on paper. These took up most evenings after the kids had come back from an already stressful school day, and cost huge amounts of money.
After a few months of this, we looked at our relationship with the kids and it was getting worse. We could only see them as a project, not as children any more. We'd trained as ABA therapists to cut costs too, so we'd fully bought in to the whole thing (Disclaimer: I'm sure ABA is very helpful for lots of kids, it just wasn't particularly for us).
We decided to just treat the kids as children, who needed to play and be loved and listened to like other children. We had (well watched) play dates instead of therapies, and got the kids to talk about feelings (theirs, and others'). We did homework in the evenings (their school work had been going down hill) and when it was finished, it was finished.
They're teenagers now. They're not social butterflies exactly, but they have (a few good) friends, and can relate to people, and talk to them when they need to. They love our pets, and relating to them has been very good for teaching kindness and empathy. My eldest was 'given' 11 GCSEs by his school last year, with very good grades. He's doing 4 science/maths A levels, and is very chilled about life and likely to go to Uni - although he'll probably live at home for it. He was considering applying to Cambridge, but he now thinks it may be too far from home.
My youngest has always had one very close best friend, although the actual friend changes. I'm hoping those skills mean he'll have a very close girlfriend eventually, although he's still young for that now. He'll do OK at GCSEs too I think. Although he has problems sitting exams because he gets too stressed, we and the school will work on coping mechanisms.
They love me, and their Dad, and each other. We still hug each other often, and watch films together on Friday nights sitting on the sofa, and though they've never been good at saying they love me, they show me in lots of different ways and even when they're at their bolshy, teenager worst, they know there are lines they don't cross because they don't want to upset me.
They're affectionate, and happy doing their thing. They show every sign that they'll have a good life. It's not as bleak as they made out at the start by any means, although over the years we've had to put in a lot of hard work with them, and have had to stand our ground a lot when people have tried to write them off. Be prepared to be very firm with schools and professionals, and you'll be amazed by what your son can actually achieve with your help and support!