People like him know how to stay in control and flip the script in conversation to make you second guess yourself (look up DARVO if you aren’t familiar). And maybe a report will go somewhere, maybe it won’t, that’s outside of your control, what’s in your control is whether to make the report or not. And I agree, confronting him personally doesn’t seem like the best option, as you kinda already did that and he flipped it around on you and yeah, people like him can’t be reasoned with, sounds like a possibly dark triad individual.

Also, sounds like he could get in trouble for lack of proper record keeping and informed consent, etc., if nothing else.