Kim,
Now that I have more complete information, I can better advise. Your son is an HbE beta thalassemic. This can manifest as either transfusing or non-transfusing thal intermedias depending on the severity of the beta gene mutation. Your son's HbA is non-existent. His hemoglobin consists of HbE, caused by a common Asian variation of the beta gene, HbF which is produced by the neighboring gamma gene, and HbA2 produced in small quantities by another neighboring gene. No normal beta globin is produced by the beta gene. This is beta zero and when combined with HbE this is likely to require transfusions.
The way you describe your son's health and activity level, he does appear to need regular transfusions, perhaps once a month, maybe a little longer. The problem with this is that it does add iron, which means after awhile he will need to begin a chelation program. The other problem is that he risks more antibody reactions with ongoing transfusions. This is also a common transfusion related issue and it causes the spleen to enlarge as it removes red blood cells. In the past, the routine was to surgically remove the spleen to slow down this process, but this has proven to not be a good policy in the long term, as it can lead to other problems as patients age. It should not be removed unless there is a clear danger of rupture. Talk to the doctor about your child's apparent antibody reaction to the transfusion and see if there is anything that can be done to more closely match his blood for transfusions. The Hb should not drop within a few days and as long as it does, antibody reactions are the most likely cause. If you can get him past this and on a transfusion regimen when needed, his overall health should improve dramatically. I have heard this often in cases of thal intermedias. I am sorry that the doctors won't cooperate and try hydroxyurea, but perhaps in a few years, once this new drug is marketed, the doctors will be much less reluctant because this drug is being developed specifically for raising the Hb, especially in thals with Hb levels in the range that your son has. This drug is being tested in Asia also, so I do believe there will be real attempts to get this drug into the hands of Asian patients. I expect that we may also see some copying from certain drug companies in Asia, as there is with chelators. So, keep hope. I think the best thing right now is to test his Hb regularly and transfuse when needed. I do think with his lowest recorded Hb level being 7 and a high HbF, that he is an excellent candidate for Hb inducing drugs.