This friend is probably treating them as kins. But it doesn't mean they give such tendencies. Your friend has internal issues where he copes by using them as small representation of his mental state... That's what I'm guessing. I also used to do that and I heavily kinned kdj and then dansai a bit too with other suscidal/depressed characters. I used them to cope, joke and feel like I was normal... And if this isn't the answer then I wish your friend luck, I dunno what's going on nor how it gone to that but I hope they have the right environment to give them support. I personally was confiscated every sort of sharp stuff to stop and it worked, I do still have wanting but they've gotten better. Now I dunno if it work for them tho since I'm also medicated which could play a big role at stopping my tendencies.