This is obviously very frustrating for you. There is a good chance that some relief is possible. It is possible that in part of the cleft palate tissue there is some deviation in the alignment of the nose and sinuses. This can be the cause of the sinus infections and ear infections. Allergies may or may not be increasing the problem by causing additional swelling and drainage. A good examination by an ENT surgeon and possibly by an allergist should answer these questions and help in the process of providing answers and relief.