Be there for him and keep insisting there are other ways. There isn't much you can do for online friends, especially if they fail to login to the program which is your only form of communication.

Real life friends and online friends are different in this aspect, as you stated you would do something, such as notifying someone of his intentions, but you are unable to.

I wish you the best of luck, be a friend and if he logs on, be there for him, do not give up on trying, you'll regret it later in life. But if he does change his mind, as terrible as this sounds, take everything with a grain of salt. I do not want to sound like an ass, I really don't, but a lot of people who change their minds don't really change their minds, they predominantly were looking for some form of attention, this isn't always the case, each case is different because of its own mitigating circumstances, but it is something to consider.

Has he given his games accounts up? That would be truly a terrible sign, as gaming accounts to a gamer means a lot to them, it is what they have worked on for hours at a time.