Is this a typical case of a ‘lil miscommunication, or are we missing a big piece of the puzzle here?

A perfect pick-up truck (after sitting in the dust for 5 years) has finally been fixed and passed down to this deserving granddaughter, name on the contract and all. A gift given to her by her late grandpa, who knew just how much she would appreciate it! However, a spanner is thrown into the works when her sister claims that their dad offered it to her boyfriend…a story that makes absolutely no sense, as he was the one who fixed it up for this daughter…

So someone is lying here, and we want to know whose hands are painted red: Will this sister do anything to get her claws on the truck, even if that means manipulating her family with contradictory ‘he said, she said’s.’ Or is this father too scared to face his daughter, and tell her that he too participated in this sly arrangement to fender-bender her plans of inheriting the sought-after truck?