We recently lost my 14 yo niece in a car accident. Just be there for your friends. Some days they will want to talk and some days they won't. Just let them know you will be there when they need you. It is ok to cry and also to laugh with the parents. Take your clues from them. Sometimes when we are with my s-i-l we don't know what to say or do but she knows we are there. My son had his hs grad. the weekend my niece would have turned 15. It was a tough weekend for everyone but we were all there to support each other. We shed a lot of tears knowing that my niece would never take part in any of the things we all think about as parents(graduation, prom, college, marriage, haveing children) These low points will be triggered by everyday things and there will be lots of good days and bad days. My thoughts are with you and your friends. Just be there for them.