Isn't it normally code to have a fence around a pool? So even if he had a medical episode while riding a lawnmower, surely a fence would have stopped the mower.
I have to imagine that he refused to have a fence around his pool because big government can't tell him what to do, so perhaps this death is from hubris.
It's very likely a requirement to have a fence which would prevent people from outside your property accessing the pool, but not a fence right at the edge of an in-ground pool (which this must have been for a riding lawnmower to plunge into it).
Some states, cities and counties have laws that require a perimeter fence around the pool to keep little kids safe. And as I recall, the fence usually can’t be your yard fence. It has to be a separate fence with a self-closing and self-latching door.
And even if local laws don’t require it, insurance companies may still charge you out the ass if you don’t have it and keep the gate shut at all times.
I think those codes depend on the state and it may depend if it is empty or if a child lives with you but even if there were a fence, they are normally pretty flimsy and meant to keep young children from getting in unsupervised. A ride on lawnmower is going to tear though one super easily.