I believe him tbh, he has nothing to be pressed about, TEOG video turned out to be underwhelming when he was fired and he's directed some of the best pop music videos of the last decade, it's not like he needed Gaga or anything. He has no reason to lie.
I wouldn't be shocked. She did admit to having a drug and alcohol problem and they've never gone away IMO. Even when she was on Watch What Happens Live she said she was addicted to a lot of **** and it sounded like she was hinting to be suffering from these addictions while on the tour.