Spent a weekend in Paris with wife and daughters throwing up, including into my hat in a shop, cleaned up and generally dealt with it, including cleaning out the shower drain and going to a French laundromat. I expect they'd have done it for me.
The concert would no longer be any fun because I'd feel guilty if I even attempt to still go or do end up going after taking him back home. Plus, it wouldn't be entertaining if it was originally scheduled to enjoy it together. I would help clean the mess up and return home.