You say he had no proof. You do not know.
I postulate/speculate he did have proof. This would explain his targeting the 13 yr old.
More speculation, maybe the 13 yr old had threatened the doddering old fools life? It happens. Gangsta rap aint about going to church picnics bro.
He might have been in fear of his life.
I have little doubt of that...it sounds like he was surrounded by people (and I use the term loosely) who were victimizing him just because he was an old cracker...