Complacency kills, accidents can and do happen at any experience level. In fact I’d argue they may happen more with those who have grown too comfortable with firearms, usually the newbies are appropriatly cautious. I’d be real interested to see some data on that but idt anyone is compiling it.

If I had my guess as to “why,” your buddy sounds like he falls into this trap (at least when drunk, which tends to exacerbate feelings of “Ah shut up I know what I’m doing.” Lol) Hopefully he’s better about it these days!