Glen was the one who crashed the car and Hank took the fall
Why are people on this forum acting like this is under debate? It's not at all ambiguous.
The judge spent decades hating Hank for ruining Glen's baseball career when really it was Glen's fault all along. Adds a tragic layer to their relationship, make Hank seem loyal and principled (he could have told anytime but he chose to protect his brother) and makes Glen seem like a total coward.