When you're unhappy and demoralized, or don't see hope in the future, and thoughts of self injury or suicide begins to enter your mind, and all these feelings last for several weeks, that is depression. Just that it could be classified into mild, moderate or severe depression, in which case you'll have to see a specialist.
In most cases what victims need is a little more understanding, love, care and reassurance from family and friends and possibly counseling.
Now that he has reached out (that's if doesn't do a 360 tomorrow), I hope his family and friends can get/give him the help he needs.