When I saw that I wondered if the Grandfather knew and wanted to get rid of the pistol.
Pawning doesn’t make anything disappear. That’s a long time for a gun to still be in a pawn shop unless the kid told him recently. Either grandpa isn’t the smartest thing or he didn’t know. Wonder if the cops knocked on his door at the time and what he told them.
Sorry, that little monster can’t be saved.
Grandpa likely noticed there were missing rounds. And certainly he noticed that there's a dead guy in the trailer park when the police showed up and started asking questions.
Maybe grandpa is an alcoholic who wondered if he killed the guy during a blackout? 100% speculation on my part.
Or the Grandfather killed the man and convinced the child that it was him instead.