Yes, I agree with Jim. Drugs only mask a problem if used to avoid the emotion. If you believe your friend is suffering from depression, you can encourage him/her to see his doctor or a psychiatrist in which appropriate medical intervention would be applied. But in general, when we use an outside substance to numb the pain we are asking for trouble.
I think Jim is also right. Just be there for him. Encourage him to stay busy. This is really the time to pursue all of his own interests. Whatever hobby he is into, get really active now. Throw himself into work or school. Seek out time with friends and family. Exercise is really great when we are under stress as it releases the bodies natural happy hormone. Volunteering also does amazing things for the psyche so I'd encourage him to find a way to give of himself as it helps one's own mental state. If he is at all spiritual, church can be a good thing during a difficult time. And counseling is also of great benefit to sort out feelings.
Good luck
Drugs are most definitely not the answer..put that out of your mind and don't even think about it..alcohol is not the answer. Take it from me..I lost my son 2 years ago and tried to cover up the pain with drugs and spent months trying to get off of them...
The best thing you can do is be there and give this person support, an ear to listen, a hug, time spent enjoying things..movies, walks, talks. or other excerize...
Just be there as a friend. Forget about drugs. Drugs will only lead to another broken heart and serious consequences.
Jim