On a positive note, I had quite a bad concussion due to a playground accident when I was your son's age. I effectively lost my sight and had nausea for months afterwards. I was taken out of school for at least a couple of weeks from memory. Then I went back but I kept getting mild nausea.

It got more and more infrequent till, in the end, it went away completely and I made a complete recovery. Fortunately a child's brain is quite plastic. I don't think that I suffered much loss of intilligence due to the injury, although I suppose there is not telling how smart I might have been!

I think that you are doing the right thing to treat it very seriously, but perhaps you can be optimistic for a good outcome at the same time.

Good luck.
CS