Edge of Winter (2016) on Netflix

Plot summary

Karen and her new husband leave Bradley and Caleb with their father, Elliot Baker, while the two of them take a vacation. Divorced and just fired for punching his boss, Elliot sees the visit as a chance to build a relationship with sons he barely knows. In his bedroom the boys find a shotgun, and after he yells at them he apologizes and decides to teach them about firearm safety. Driving the boys to his old lumber yard in the wilderness, Elliot finds text messages on Bradley's phone complaining about the visit and hides the phone. At the yard, Bradley ignores Elliot's instruction to keep the gun close to him, and the kick knocks him to the ground. On the way back the car goes off the road and gets stuck.