[Vuizur]

He apparently got divorced and moved out of his home country. And here he has no social circle. There are of course hopeless cases, but he is not mentally ill, only alcoholic. It is possible that he will never overcome alcoholism, but it didn't look like he tried treating it or anyone suggested it to him.

It is easy to be lonely, I have talked to several charismatic and very cool people who complained about how hard it is to make friends in a new city. This combined with other negative factors can cause people to fall in a hole. (Of course, people who are delusional about their AI girlfriends like in /r/replika are also sad.)