One of my Uncles had a mental problem and had been hospitalized 2 times for it.

He thought that folks were out to get him,Paranoid to the max.

As long as he took his meds he was ok to live by himself.

That said we regularly went through the house looking for weapons.
Back then anyone could buy guns from a pawn shop.

He should have been kept in hospital after the second time he went coo coo.

The family has a part to play but safeguards should be in place.