Eating Problem

My son is 7 yrs old and autistic he eats very few things. How can he start tasting and eating other things like meat, fish, chicken,veg,lentils, ive tried everything but he just doesnt taste he is only on fries and biscuits. he goes to mainstream school with an aid he is in grade 1 but still very much behind grade level he likes to be social but lacks in two way communication any looses interest quickly but his memory and road mapping is excellent pls tell me what to do? biggest problem is to make him eat normal food

A friend has child like this. There are liquid vitamins that she is adding into the things he does like. eg. strawberry milk.
There are lolly pops that contain vitamins too, check the chemist.That way he can continue to eat this way and you can compromise on the nutrition.

It is about sensory issues with textures of foods and control.
It is very well and good to want to have a child that eats everything but lower you expectations of normal parenting techniques. You will only make changes one step at a time.
My friend caters to this but make sure that you get one scoop of a different food with all the other things he does like. Use If THEN statement.
IF you eat a little of this THEN you can eat all of that.
He can be stubborn and possibly not eat at all.
Does Dad sit at the table with you? Modelling from admired people can promote a try.

With my own on the spectrum, I took the hard line early. They eat what is on the table or go without. most children only last a few days. But with the anxious and controlling kind they can last up to a month without eating which is bad.