Personally I think he lasted a long time. I imagine it is more similar to the condition where reflux from the belly causes a reflexive shutdown of the breathing passages, and less similar to choking on a piece of fat. In my little life experience, the former is the more memorable (even if much less dangerous) affair, causing an instant urge to stick the head up as high as possible. It occurs to me as I write this that that urge may be related to defense from drowning.
(As for choking, be very, very careful when eating pot roast. Chicken bones do get lodged in the throat and have to be removed, but choking to death is more likely with a lump of fat.)