Okay, first of all, this film is a goddamn classic.
Listen, if you haven’t seen this, let’s just spell out the plot for you, and if you can’t see why this is such a movie for your dad you don’t belong on this site.
Sylvester Stallone is a truck driver (!) who also participates in professional arm wrestling competitions (!!) and has to win the World Arm Wrestling Championship (AN ACTUAL THING!!!!) to win back his son (*explodes out of the sheer dadness of it all).
Like I said, this movie is a classic.