Check out the possibility it's casein.
thanks for your advise he was already tested for celiac and came back negative ,he also had the gentic testing and also came back negative. the doctors have tested him for almost everything out there but everything is negative i dont know where else to look
If he can't drink milk, it may not be the lactose that is a problem. It could be the major protein in milk - casein. There are many who can't have ANY form of diary. So if you've noticed that is part of the problem make sure nothing has diary in it in ANY form - that means sodium caseinate, whey, etc.
In addition, those who can't handle casein may also have a problem with gluten. Check to see if there's any celiac disease that runs in your family. Have him checked for celiac and in addition to blood tests or whatever, make sure they do the genetic test (allele). If that turns out positive - carrying the genes - he HAS to be gluten-free as well, even if the other tests show that he isn't presently ''celiac."