I would say that I think it’s weird because I think shaved pubes are weird (and experienced horrific razor burn when I tried it back in college).

Sounds like you are a fucking rockstar dad though. That’s a very vulnerable thing to think about asking your parent for a teenage boy. Lots of self-consciousness and trying to figure oneself out. That he felt comfortable asking you says a lot. That you stepped up to ensure that he knew how to do so safely says a lot too.