First, with a child that young, I would first talk to your doctor or a nurse.
Second....he's not going to starve himself. Don't give him the foods he'll only eat, only the foods you want him to eat. He will eventually eat them because he's hungry. This is what my doctor told me once. He won't starve himself. Babies are smarter than you think, hehe.
Another option, have you ever tried to trick him into eating something, like, chicken covered with melted cheese? or ham? Things like that might work.
Even though I have been through somthing simular, I would still contact your doctor or nurse. They might hav eyou come in to watch his weight while you try some thing to get him to eat.
It also could be a phaze. You never know with kids, hehe.
Good luck!
H.