From an individual perspective, I say give the guy the opportunity. The accident was eight years ago, he has apparently had no issues since then, and he's made demonstrable effort towards making something out of himself in the meantime. Further, he's applied and been rejected multiple times, made improvements, and then tried again, so this isn't something he's doing because he doesn't have any other ideas about what to do with his life.
From an agency perspective.... In today's society, the potential fallout far outweighs the benefits of a redemption story. He's painting a bullseye on the organization, and no amount of do-gooding is going to matter much in a lawsuit in front of an unfriendly jury.
I think he could be a better asset to his community outside law enforcement. Just a non-cop's 02¢.