Did your son mention how he sounded when he did sing?
We were there for the concert and he has pretty much lost his voice. He has a few notes that are good, but most of it is pretty marginal. He explained he had lost it and it was coming back..... something about vocal paralysis..... I think.
I thought he should be given credit for even going out and performing at all..... but my son said he makes up for it with his demands, as though he is still "it".
Quite a bit of the concert was stories and history, but his son has a wonderful voice. Art treats him like crap as well.