He's got a few hours until he passes away. A close friend is dying. Help?

My brother's best friend was involved in a terrible car accident and he's currently unconscious and in hospital. He's on life support but they said he's only got a few hours until he passes away. I got the call about 10minutes ago and I don't know how to tell him. It will break his heart and I need to know how to support my brother before the time is up. Sadly, the friend is far away and we can't visit him.