Later he open up to have been using $500 for gambling per day, he said all these started when his wife left him, that he isn't into gambling at all, but I can't ask why his wife left him in the first place, but does loneliness make people become addicted to gambling or it's something else.
There is no connection between loneliness and gambling except that person is already a gambler then he can utilized the opportunity of being lone to start gambling more or making some random deposit to his account to constantly keep gambling. Sometimes is from mindset what you think of is what mostly come into mind, and I don't see any reason why someone wife will leave him and he turns himself into gambling addiction instead of becoming a drunker or smoker because these two things are easily being triggered by loneliness and not becoming an addicted gambler.
Quite reasonable and your idea is almost the same as what I have in mind, people say that loneliness can trigger someone to get involved in gambling, I agree for that matter but on the other hand this idea only leads to those who have previously known or have been involved in gambling or even still quite active, because for ordinary people who have never gambled at all I think it is still unlikely for them to suddenly enter gambling to get involved in it, the scenario will not be that simple.
In general there are a lot of people who experience loneliness at certain times but not all of them are gamblers and that can kind of invalidate the idea that loneliness can trigger gambling, like I said that idea would only apply to someone who is already familiar with gambling so like you said that at the same time they are trying to take advantage of the time and opportunity to gamble and try their luck. Basically and overall there are still a lot of things that they can choose to do as an alternative to loneliness, playing online games (without risk), watching a movie or chatting something with one of their friends via mobile phone has the nature and potential that they are very likely to choose in general in such situations.