school not meeting sons emotional needs

Hello!

My son has a diagnosis of ASD and he is 10. People describe him as high functioning ASD as he is not delayed in his educational ability, its more emotional regulation and anxiety. He is in mainstream school, year six and is really struggling to cope emotionally at school, having regular meltdowns, which then takes along time to contain after school.

I'm really concerned that his emotional needs are not being met at school and the meltdowns are becoming more frequent. He is in a class of 30 children with a teacher and a TA.

What is the best way to assess if his needs are being met as I feel at a loss of how to help him.

Any advice gratefully received.

Thank you