Absolutely. Why not? It may not "help" anything but all things don't have to "help", she does not need to be protected from this stuff at all, ever.
I would state it in a non "blaming" way, of course, but she should be aware of her behavior, not just that it was toward your Son.
That an 8 year old would ask this:
"Dad, that was weird at dinner. Is mom okay?"
That's not really normal behavior. Worrying about your parent at that age shouldn't be an issue at all, but it surely is.
I can't remember COD, have you talked to your Son about his Mom's alcoholism? If so I'm guessing he may not have caught it all (and why would he, he's a kid!) just that it might be time to review it all with him so that he's not confused when his Mom is not mentally there.
He's obviously a smart kid, understanding the science of alcoholism and how it affects the brain is probably well within his understanding now.
If he understood he wouldn't be asking that question?