You weren't the only one! It's actually a pretty intricate comic. You have to infer that it's his dad from 1) the age difference between them in panel 2, and 2) the punchline itself; you wouldn't pull the plug on a random old guy, it would have to be a family member. So the joke doesn't work unless you get the joke. Somehow it still works, though.
Did you just link an hour long video without any heads up whatsoever? Who's just free to sink an hour into a random joke from a stranger on the internet on a whim?