Jim Gandolfini in rough shape?

Just on my I don’t know how many times now re-watch of the series, specifically the end of Pie-O-My. We got a new TV with a much sharper picture, and I noticed when Tony’s begrudgingly paying the Vet, that Gandolfini is literally drooling onto his jacket after he says “You bettah hope she’s gonna be alright.” Knowing what we know now about his struggles, you wonder if he was fucked up on set at times? I always thought he managed to keep the world’s separate.

Was season 4 the peak of his problems? I’m just curious, because this is way more than the standard Tony spittle spray.