I understand, it is difficult to say no to a friend, especially when things like losing their car or getting kicked out of their house is concerned. I suppose that it is all based on the situation.
If I have the money, and a friend is in trouble with no fault of their own, I would gladly loan whatever I could. I have a friend who is one of the best guys I have ever known. He was laid off about two years ago, and when he couldn't find another job he started a contracting business and built it up himself, eventually hiring two other employees, making decks and other home improvement projects. He finally met a woman that I approved of, which is important because he's my best friend and has been screwed royally in the past, and got engaged, set to marry this June. Put himself through school, was a foster child bouncing around from house to house until his 18th birthday. He's an amazing man, and he never gives up. Then last summer he was blindsided by a semi driven and owned by a mexican company, and the "insurance" has disappeared somewhere. He can't work, and has lost his business, so I and some friends have loaned him some money to get buy until he can work again, hopefully this summer. In this case, I'd give a friend whatever I could.
On the other hand, I USED to have a girl friend who was always in trouble. I've bailed her out of so many scrapes, got her car out of impound twice, and my boyfriend has also bailed her out. The last straw for me was when her car was impounded for the third time due to parking in a restricted area, and she asked me to give her the $300 to get her car out. I finally put my foot down and said no, and she went behind my back and tried to get another friend of mine, whom she had only met once, to help her. In her case, I was enabling her, which made it impossible for her to shape up on her own, she just assumed that I would always be there to bail her out. We are no longer friends, but hey, I am not made of money myself!
Basically, if this guy is a really good friend, and you really want to help him out and can afford it, then buy the gun, but never expect to get the money back. Let him know that this is the last time you will bail him out, and tell him that you think he has a serious problem. I have found that friendship means not only being there for the good times, but I also let my friends know when I think that they are screwing up. I appreciate it when MY friends give me a reality check. It could really be that no one has sit him down, and told him that he's got a serious probem that will only get worse, and that is destroying his friendships because they don't want to bail him out anymore. If he's really a good guy, he'll get the message and shape up. If not, he wasn't worth helping out in the first place.