If he has nerve-based deafness, cochlear to brain, there is as yet no on-stream surgical solution. Connecting individual nerves is still some way off. If it's the hearing bones, that can sometimes be fixed. Assuming he's getting the necessary medical attention, I would be paying particular attention to his communication and reading skills... help him find the best way that suits him to learn things and interact. Reading is very important because it may be his richest and most easily accessible resource for learning things throughout his life. Encourage him and get him comfortable with it; patient persistence. The internet is a godsend for deaf people, so teach him to use it to his best advantage.