Its really hard to connect a sudden event like this to a relatively benign surgery i.e. toe amputation. I cant envision a scenario where the surgery was a direct cause of his death. If it was a PE and he wasnt getting SQ heparin in the hospital, maybe you have a case, but even that might be a stretch. The vast majority of deaths in the hospital were beyond anyones control, but of course there are exceptions. Despite popular belief, its hard to kill people.I think it's most likely that they didn't make any mistake that caused this death, especially with just an amp of a digit, but I would think this definitely would deserve an autopsy. He probably had a PE, STEMI, something catastrophic either unrelated to the surgery or a very unfortunate complication of the surgery, and was in a part of the hospital for very non-acute patients that don't really need much monitoring when it happened.
Is there a way to get a coroner to do it? The county coroner said they won't since the surgeon signed off on it, so as far as I'm aware I need to get a private autopsy done, which is a pretty large financial burden at around $7,000. I'll absolutely pay for it if it's at all likely that they messed up. I can't stand the thought that they could face no repercussions for any mistakes they made.