Truck died at dump station

I saw something similar at a motel during deer hunting season a couple of years ago. A guy's trail blazer wouldn't crank and couldn't unlock doors with the key fob. He unlocked the doors with his key, asked me to give him a jump although I figured it wasn't a battery issue because when he tried to start it, the headlights didn't dim at all. Then the nest time he opened the door, the security system activated, I guess to make sure all of the hunters were awake! He couldn' shut it off so he disconnected the battery. About five minutes later he re-connected it and. viola!, everything worked and off he went. That night when he returned he said it never bothered again. By the way, he didn't get a deer either.