Tzatziki sauce can help too, but having, knowing and sticking to your limits is a better plan. I suspect that, once that chunk of pepper hit his stomach, he was in for a long night, regardless of what he ate or drank.
Glitch, there are some spicy foods that also taste very good. A local wings place has a couple of them. At lower powers ("911") the flavor is good and the heat is manageable. Up a level though, and it's not for me. And I was eating raw chills before I was a year old (and supposedly really liked them.) Mistakes can happen, 'medium' can cover quite a range in restaurants (there was a good Thai place in Oxford once. If I ever get back there, I'll settle for their idea of 'mild'. I hope.