Did he have previous cancer in his testes?
Did he undergo chemotherapy and radiation?
Brain germinomas are quite rare. They are usually very responsive to chemotherapy and radiation. I cannot explain why your son passed 5 years later, especially without reviewing his records. I am sorry for everything you have been through and are going through. If you feel you need further information that I cannot provide, please feel free to relist, and perhaps change your question to the Oncology section.