Good point about the humor. My ISTP father likes to say that all he really wants out of life is a couple good belly laughs a day.
With Fe as his inferior function, he doesn't want people to come around with a lot of problems. Being an autonomous person, he prefers that others be autonomous as well. When the kids get needy, he just wants to escape. So I keep it light. I let him know what's going on in my life, but I make it ckear that I'm on top of it and I'm not looking for help from him. Then he gets curious and asks questions.
That is, he is intellecturally curious and wants to learn about other people's affairs, but he doesn't want to get dragged into other people's problems and have to provide solutions. So I make it clear that I'm on top of my own problems, and then he relaxes and becomes interested in my affairs just as an intellectual exercise.
Other than that, he likes to mentor. But he wants to mentor about the stuff that interests him. Stuff he's tinkering with, yardwork, etc. So I let him talk a bit about his own stuff.
And again the humor thing. I quip a lot as we talk, and he loves it when I use my Ne to spin the world into humorous combinations. I keep it light and give him those couple belly laughs a day that he likes, and we get along great.