Eating habits..

Hi so this is kinda just gonna be a rant I guess? I'm so stressed about this and cry all the time feeling like a terrible mother.

My 2 year old son is autistic and we can't get him to eat hardly anything. We've tried so many different foods but he won't even entertain them much less try them. We can't force him to eat it. The only things he will eat are chips, McDonald's fries specifically(but even those he's not eating now), sometimes he'll eat pop tarts, occasionally he'll eat a PB&J, and a little bit of ramen.

I don't know what to do at this point because he won't try anything new and he hardly eats. I feel like a horrible mother because he doesn't eat hardly anything and no matter what I try I can't get him to eat new foods. We have to give him pediasure at least 3 times a day so that he doesn't lose any weight. I just want him to be healthy. I wish he would eat just at least a couple more real fulfilling foods that aren't straight junk. Like Mac and cheese, chicken nuggets, pizza, grilled cheese something!

Do any of you struggle with this as well? We don't believe it's a texture issue but we have wondered if he possibly has ARFID.