We use the Finishing Touch Flawless Brows Eyebrow Pencil Hair Remover and Trimmer - they have it amazon, target, cvs, etc.

You’re way overthinking this. Waxing or threading will be fine. Or give him some tweezers and tell him to work on it a little at a time.

Just let him get it waxed and stop micro-managing HOW it's waxed.

Have them thread it. And tell them that you want it to look natural.

Why not just use tweezers?

A competent person at a salon should be able to wax it while making it look natural. You could also look into laser hair removal, as that would be more permanent.

My teen boy has a unibrow. He doesn’t like it and wants it removed. Is there a method that will look natural? Maybe leave a couple of hairs? I don’t think waxing or threading will do the trick I think that will make it look too delineated and unnatural.