How do I help my friend that witnessed a murder?

One of my good friends witnessed a murder recently and has lost friends because of it. I don't want to get into details, but due to the situation I'm almost certain they will experience survivors guilt at some point.
I want to be a good friend and try to help them but I'm not very good at this sort of stuff, and I know there's only so much that I can do, like just being supportive and being there for them. But does anyone have any suggestions?
I thought that this might be a good place to turn to for advice.

My answer isn't really in regards to what you can do, because I wouldn't know what to do in your situation either. Is your friend seeing a therapist or counselor? Watching someone die can be really hard on someone mentally. It might be very beneficial for them to talk to someone like that.

The police were talking about getting my friend some free therapy. Let's hope that actually works out.

Reznor wrote:

The police were talking about getting my friend some free therapy. Let's hope that actually works out.

Paid therapy would be better. Some forms of free therapy suck... I know from experience.

Ivan wrote:

Paid therapy would be better. Some forms of free therapy suck... I know from experience.

I agree. I will definitely encourage them to get some better help.