Coma guy ought have died of dehydration. The hospital looked to have been abandoned for a while, and to have had damage from explosions (grenades?). It'd be doubtful that his IV would have kept being topped off. I can't imagine coma cases would have taken priority as things went down hill, supplies ran out, and staff ran out either. Hospitals only have two or three days, at most, of supplies without resupply. Emergency power was still on in a limited capacity, but the rotting bodies and general disrepair suggested that the place had been abandoned for a long while.
Water taps running... questionable. If the town had a gravity feed system from a reservoir, perhaps. But no power means no pump stations and no purification.
I wouldn't have expected any guns or ammunition left at the police station either.
Yeah I know... but if one thing is going to be extraordinary, everything else ought be by the numbers and as close to realistic as possible.
That the one father had no qualms about teaching his son to shoot was a nice touch. It was just accepted.