Fathers tend to be the subject of jokes, and that's okay. They joke too, and most that I know can also take them. There's a lesson there, one of many which our dads have taught us. It might be their most important lesson: have a sense of humor.
Many things in this world are important and need to be taken seriously. Yet we aren't going to save the world. Indeed, we often must simply take a step back and regroup. Humor helps us do that.
So have joke with old man today. If he's gone, think about his jokes and laugh along anyway. Yes, even the ones he told dozens of times. If he liked them, why shouldn't you?