Try not to be anxious, first. Kids sense that believe it or not. It can cause undue stress over the whole thing and leads to anxious kids in the long run. Remember, kids for the span of time have had their own eating issues and grow up to be healthy, happy adults (and some, eventually fat and happy, ha ha). Since he has a milk allergy, you might consider consulting with a nutritionist. I love that specialty. They are a wealth of information and ideas. I had one child who was not a meat eater. Still really isn't. We just worked on protein in whatever form. Will he eat smashed beans? Baby food meats are kind of . . . well, they don't smell good. It's okay if you figure out what he likes and give it to him over and over. I'd speak to his pediatrician. And . . . a common patter is for kids to eat their vegetables but at right before age two, for them to decide they hate them and not eat them. Happened to my kids. One is not a picky eater at all. He came back to eating his vegetables at age 4. The other has never like them. Things like cantelope have similar nutritional value as vegetables so don't get caught up in the fact that he has to eat X to get all the nutrients he needs. Does he like oatmeal mixed with fruit? Try mixing something he likes the oatmeal with say some carrots. Get creative.
So, I just read this. How is it going now??