I like you and all man, but that's really stretching it--big time. If he's able to push that kind of weight, RAW, for 10 sets of 10, I'd estimate his 1RM to be in the area of 700-800 lbs. Unless of course your friend doesn't train for power but goes for the health look.
Let me tell you what I do know about the guy... Which isn't much.
He's jacked... he is about 5'6" (maybe shorter) and weighs around 190... When I saw him lift... It was like this... 1 warmup set at 225... the next was 315. Those 10 reps were like nothing... He kept that weight on there and stay on the flat bench for the rest of the workout.
Now... I don't know about a max... I've never seen him max ever... His arms are massive though... Easily 20 inches and even though he's not "HUGE" he looks big for his size.
This is a guy who's been lifting for a long time and has always been one of the strongest guys in the gym... Was he on the sauce, probably, but I have no fact to base that on.
As an aside item, I don't think I ever saw him train legs ever... maybe once in the 3 years I lifted around him.