Not DS, but YS DD11 missed some class time because of some advanced classes that did not quite match up time-wise in the past. How successful that arrangement was really depended on th teacher. I tried to stay out of it, as much as possible and it usually worked itself out. A couple of times I found myself biting my tongue...but it always worked out.
Your DS is a bit on the young end, so hard for him to work everything out on his own. If you think his teacher is supportive, I might reach out to him or her. Unfortunately, not all teachers are supportive of SSA and this could come out when you try to have this conversation.
