Is my friend depressed? How can I help him?

ye, your friend does sound a bit depressed. it is probably because something happend to him and he doesn't feel like he can share it with you.

my suggestion is to come to his house with a couple of other friends and do an "intervention" - start asking what's wrong until you get an answer.

WebMD in conjunction with the Cleveland Clinic has an outstanding

Dear trying to find out what are the reasons behind his depression and start works on reasons to find the solution. You can gift him some inspirational quotes written books that encourage him to take everything positive.