Hi Emy,
There isn't much recommended for treating HbH disease. Hopefully, he won't need transfusions. Transfusions are usually needed only when the patient carries a non-deletional alpha thal and has worse symptoms. Folic acid is the only universally recognized treatment and your son should start on folic acid drops as soon as possible, He should continue taking folic acid daily for the rest of his life. Folic acid is needed to build red blood cells and is one of the few things you can do to help. You should watch for any relation between foods he eats and him feeling worse. Fava beans are to be avoided, but some people show sensitivity to other beans and legumes, so if there is a sudden drop in Hb level, check what has been eaten. If beans or peanuts have recently been eaten, try removing them from the diet to see if his Hb stays more stable. Chemical fumes should also be avoided. We have a list of drugs and chemicals to avoid with alpha thal at
http://www.thalassemiapatientsandfriends.com/index.php/topic,3410.msg34830.html#msg34830A healthy diet is highly recommended and establishing good eating habits when he is young can make a real difference in his life. Please resist attempts to correct his Hb with iron. This is a mistake in HbH but commonly made. With his low Hb, it is likely he will absorb too much iron from food, so taking iron supplements should be completely avoided, as to avoid iron overload.
Getting pregnant naturally means taking the chance of another child with HbH. Some people choose this and either live with the result or abort when HbH is diagnosed. PGD and IVF can be used to accurately choose a non-carrier, but it can be a long and costly process.