Worried about my son

Hey guys, I don't post a lot of non automotive stuff but I am worried about my son Aiden.
First off he is 3 years old and has been diagnosed as mildly autistic. We have learnt to live with this and as long as he is happy we deal with stuff as it comes along. He is good natured and gets along well with all his little buddies. Everyone at his daycare loves him.
Now for the problem. About a month ago he stopped eating. He has always been a picky eater with everything needing to be blended up etc. He was eating his blended food and grilled cheeze sandwiches (chopped up).
Since Christmas Eve he has refused to eat anything. He will drink Pediasure which is a food suppliment . I made the classic mistake and tried to force feed him a couple of times which made him throw up. My wife and I don't know what to do and it is creating major stress. I have it in my head that I am watching him starve. Any help you can offer or if anyone has gone thru this please let me know. Thanks