2000 Camry A/C compressor clutch question

My dad drove his 2000, 6 cyl, Camry XLE thru a deep puddle and now there's a scraping sound whenever the engine is running. When he steps on the gas, it gets louder. He took it to a mechanic that told him the A/C compressor and some related stuff needed replacing. I looked in the service manual it said that the magnetic clutch needs to be replaced. After looking on some auto parts sites it looks like there's clutch bearings.

Is the clutch the only thing that neeeds to be replaced? Can just the bearings be replaced, or regreased?

Not for nothing, what makes you (or your mechanic) think it is not something other than the a/c, such as the alternator?

Good qustion, I don't know. Earlier today I took the belt off and put a shorter one on that left the compressor out of the loop. The sound was gone.