No idea what to feed our baby

Our son has been battling ongoing health issues since 3 months old. Our ENT took him off dairy a couple months ago. Then soy. Now hes off dairy, soy, and gluten. She told us we could give him goats milk, but he threw up immediately after drinking it. Also, it's hard to find gluten free toddler snack foods that dont require much prep. I'm a working mom and really need snacks that are the grab and go type, but it's like those dont exist in gluten free. Also, he may be 13 months but he still only has 4 teeth, which makes some food hard to chew. Please help. Do we need milk? Because we have tried every non dairy milk out there and he hates it. And he cant have any form of dairy or soy, so no yogurt or anything like that to replace the milk. I'm so lost.