Might be a case where being in a group was more dangerous than being with a single partner. Nobody was responsible for him.
Even with a good partner stuff like heart attack and stroke and things can happen but.... the problem would be detected and dealt with quickly. With a large group .... well, it might take awhile before anyone noticed his absence as the problem compounds.

Everyone is responsible and no one is actually acting that way.

Safety in numbers might not be all it's cracked up to be.