I doubt that your friend's grandfather was the sole source of his rage. Once the young man puts the focus on himself, he can start dealing with his own feelings and behavior. This is the beginning of the healing process. Naturally, this is a difficult first step to take. But it's essential.
Young people are especially inclined to throw around a lot of blame.
I don't buy this kind of cop-out. Oh, and leave the baseball bats to the Little Leaguers.