As someone who did the same, I share the grandparent's apprehension. These skills are fantastic to have and very fun to acquire, but shipping products requires more skill than that.

Maybe I'm intimidated by the unknown unknowns (I was intimidated by learning all these skills in the first place, but it was much easier than I thought), but I think shipping a product at scale is rather hard if you haven't done it before.

At least, he'll have to deal with flaky suppliers, parts not fitting properly with each other, unforeseen costs, etc. I would feel much more comfortable if he had used a PCBA service to produce assembled PCBs (pretty cheap even if you don't want to do bulk orders) and a fabrication service for the face (harder to do if not in bulk?).

Best of luck to him, though, it seems like a fun project, and I want to make my own wall clock now.

Well, I think you are indeed afraid of the unknown unknows. There are more skills to acquire for him to achieve this, but he proved that he can acquire them, so godspeed!

By suggestion for him would be to check a few videos about how to manufacture small scale things in Shenzhen, spend a week or two there, and roll with a factory that specializes in low volumes.