I encouraged a friend to purchase a gun to hunt with, He later used it on himself.
I talked a friend through a purchase on a 20 gauge, advised him on what to buy, etc. A few years later, he shot himself with it. The kid was about my little brother's age.
He had all kinds of problems, never was real well adjusted. It was sad, but it was something that he was going to do eventually, either by literal suicide, or something else- a car wreck, a drug overdose, a fight. When I got the call, I wasn't surprised.