He has a reputation to keep up, and he's always been -to put it nicely- one of the biggest jerks I've ever met.

[A complete asshole, a jackass, a right bastard— he could go on in his head like that, but that was the nicest way he could say it at the very least. Still, even back then when Reyes was very clearly a pain in the ass he'd been Jack's best friend. Could take everything he threw and give it right back.

No one could stand in their way when they had each other's back.]

Probably easier to think of it as him owing you a favor.