My condolences to your friend, that is very sad, especially for the little child left behind. Just the fact that you are willing to listen is really awesome, to be honest I don't think there's much else you could do even if you were there. He's got to go through his grief on his own... but having an understanding ear is very helpful, I know that from personal experience. At least you aren't ignoring or avoiding him (which hurts like a bitch), that is really kind and generous of you considering you have your own issues and are stressed out. Make sure though you don't get overly involved or overwhelmed by his grief. You need to take care of yourself too.