Another reason not to feel guilty, if he needed anyone to rescue him, he would say it directly. Look I'm a Muslim so in fact I haven't faced something like that before in my life. Suicide is forbidden. Whatever you go through life, everything will be okay one day. I just want to tell that feeling sorry for something you couldn't handle because of lack of your information (and it's completely not your fault) maybe will ruin your life or at least make ir worse, and I don't think your friend wants that, don't you?