but that is your idea of what is reasonable, what is reckless, I look at it from his point of view, to me from reading many interviews he was concerned about his safety, he has come home before and heard a noise (washing machine) and got his gun out as he thought it may be an intruder, he was jumpy and paranoid about his personal safety,
he has said he felt vulnerable when his legs were off,
so looking at it from his point of view I can very easily imagine he wakes, it's dark, he hears a noise, he grabs his gun (which he has said he has done before when he heard noises in his home) he says he has no legs on so maybe felt he could not fight, he thinks his GF is in bed, he lives in SA where rape/home invasion is a massive problem, he acts without thinking to protect (as he says) himself and his GF, it probably happened within a few minutes from hearing noise to shots (if his story is how it happened) so how much conscious thought would he have had, he may have been acting on instinct
now I have never held or seen a handgun in my country(England) I have seen them in other countries but have still never held one, I have never felt the need to have a gun, I live in an area that is considered safe, I don't have prosthetics, so I would expect I would have done things differently