My son hates school and it’s affecting his mental health

Staying at home will lower his anxiety (not increase), because the triggers are at school.

He will always be anxious when leaving house because he knows already what awaits him there.

Autistic are capable and actively pursuing own improvement/education after reaching certain age, unless in poor mental health, and without safe place to recharge. Most of what I know I learnt myself, not in schools. Downside is no official qualifications. 

Coping is bad for us, if there is another way it should be avoided, because eventuallly it leads to burnout sooner or later, be that he'll be 30 or 40 y.o.

You see it as two choices:

1. Keep pushing him to go to school so he gets educated to certain level, but at the same time his mental health will be in tatters (unless sources of anxiety are identified and removed), making him unable to have a life as an adult, like finding job, being self-sufficient, starting friendships and family we can do that only when in good mental state.

2. Let  him stay at home, and risk him reaching adulthood undereducated. It's more likely he will pursue his own targets out of boredom, if he has means to do it, I mean access to internet. 

Staying at home will lower his anxiety (not increase), because the triggers are at school.

He will always be anxious when leaving house because he knows already what awaits him there.

Autistic are capable and actively pursuing own improvement/education after reaching certain age, unless in poor mental health, and without safe place to recharge. Most of what I know I learnt myself, not in schools. Downside is no official qualifications. 

Coping is bad for us, if there is another way it should be avoided, because eventuallly it leads to burnout sooner or later, be that he'll be 30 or 40 y.o.

You see it as two choices:

1. Keep pushing him to go to school so he gets educated to certain level, but at the same time his mental health will be in tatters (unless sources of anxiety are identified and removed), making him unable to have a life as an adult, like finding job, being self-sufficient, starting friendships and family we can do that only when in good mental state.

2. Let  him stay at home, and risk him reaching adulthood undereducated. It's more likely he will pursue his own targets out of boredom, if he has means to do it, I mean access to internet. 

Thankyou so much for your reply. It’s so hard isn’t it.  School are trying everything they can do for him but nothing seems to be working. Everyday is a struggle for him. And the waiting list for an assessment is so long.