The only way to really know if he is suffering from Clinical Depression, would be for him to actually get evaluated by a professional.
Try to understand that just because a person is having a difficult time with their life, doesn't nessasarally mean that they are suffering from a Major Depressive dissorder.
Depression actually has dozens of other symptoms connected to it that are most often very severe in nature. They can include anything from severe panic attacks, to delusional thinking as well as many physical symptoms.
I can only describe it as the most painful and dibilitationg thing one could imagine. It is a complete and total collaps of the mind, body and soul, that is so profound that you can not eat, sleep, work, play, or even function as a normal human being.
The internet is filled with info regarding depressive dissorder. There you can find a huge list of symptoms that may help you understand if he really is Depressed.