Worried about my son

I have a mildly autistic step-son (16 yrs old) and he is a very picky eater. Unfortunately, most of what he will eat is either junk food or expensive (loves shrimp). He's been like this for years. Part of it is side effects from the medications he's on. If your son is on medication, you should talk to the Dr. about this. In the mean time, keep trying to feed him different things until you find something he'll eat.