Burnout in 17 year old club swimmer

I'm sure you guys can help... I am a masters swimmer. Our son is 17, has been a club swimmer for four years, and swims on his high school team. He swims with the senior 1 group, and his practices are 2 hours 45 minutes on the weekdays and two hours on Saturdays. He is a decent, solid swimmer (state but not sectional cuts in numerous events). He is a junior in high school and is currently taking five AP courses (his decision, not my husband's and mine). His grades are good and he works hard. Recently, he has been feeling a lot of stress due to his workload in school and swimming. He told me last night that swimming isn't fun any more. He says he thinks he still wants to swim club, possibly at the senior 2 level instead, and still wants to swim high school. He actually isn't sure he even wants to drop to a less demanding group; he isn't really sure what to do. While I think his academic load is part of why he is stressed, I know that constantly staring at a black line for hours is playing a large part as well. Aside from being supportive of him and encouraging him to talk to his coach (who is my coach as well, which could possibly complicate things), is there anything I can do to help? I don't want to be one of "those" parents, but I want to do what is best for my son. Obviously I would like him to stay in the senior 1 group, but I'm not the one swimming there. His coach knows him well, as he has been with this coach for four years. Part of the issue is that our son doesn't want to let his coach down. I know it is his call, and I'm trying to stay as objective as possible. I'm sure many of you experienced swim burnout as a teenager. Any suggestions you can give are much appreciated. Kristin