God and good friends will bring them through this tragedy, try to get them to talk about their son, it helps. Be there for your son, he needs you right now.
It has been six years(May 2 & 3. 2003) since we lost our 30 year old daughter(due to Diabetes complications)and the next day we lost our 21 year old son and two of his close friends (a drunk driver hit them head on).
You feel like you have a huge hole in the middle of your body and nothing can repair it. But our trust in God and all of our friends brought us through it. Time helps ease the pain but it never completely leaves.