Danniman first I want to say that having a friend does matter and can help the person you are worried about, but as a person that suffers from Depression and has almost offed himself, as well as PTSD (or so my wife thinks) I can tell you that all you can do is open the door for the person and then its up to them to walk though it. Some times I have to agree with Sen its not wise to talk to family or friends mostly because even if you do not judge or you do not mean to judge the person, one little innocent comment will make the person feel like you are judging him. Some times its better to talk to your doctor or a psych simply because we do not have to worry about the person judging us.
Personally I will never fully tell my family or even my wife who I adore and love, everything that is going on in my head. Why because A; I do not want to burden them and B: I do not want them or do not want to feel like, that they are judging me as I do care greatly about them but I honestly do not feel like I can lean on them. Your friend may feel the same way, weither this is true or not that does not mater to him as when you are dealing with Depression the old brain is not thinking "normally"
As The Real David Charles said talk to your friend and suggest maybe a local GP or mental health person and point out the fact that A; he needs help and b: a GP or the mental health person will not judge him, and even if they do who cares you will not be running in the same social networks as either the GP or Mental Health person.
