I wanted to add, you stated this: "We homeschool, so classroom modifications aren't necessary."
This is going to do him a disservice in the long run. He needs to learn how to function in a big noisy classroom, how to recognize what his needs are, how to ask for them, how to push for his requirements when they are not given or not given properly, etc. This is because you can't homeschool him for college. He needs to learn to have the strength to stand up in class and say "hey, I can't sit in this spot and I need to move to a better one", things like that. Being able to do these things will have a direct impact on his success in higher education, and life in general.
Also, make sure you have him get regular checkups with people like speech therapists, because as his mom you're much less likely to notice small amounts of speech deterioration until it becomes a big thing and then it's more difficult to correct.
It would serve him in good stead to get classroom instruction at all stages of his life. I'm not saying you have to send him to school. He can take a class in addition to what you do. This is because he needs to learn to manage social dynamics in a classroom as a person with a disability. He needs to learn how to handle group discussions, because not everyone will want to allow him to speak. This could be because they don't want to deal with the extra effort it takes to involve a deaf person in a discussion full of hearing people, or the others don't know what to do so they ignore him, or they get pissed or frustrated. It's important that he learns to deal with all these things.
I'm sure I'm missing other reasons. If he never experiences these kinds of situations before he goes to college or vocational school, that means he won't have the skills to deal with them in the high pressure environment that higher education is. And that sets him up for failure before he can even start.