Did she try securing the ice tray with a bit of tape as a temp fix? My old fridge rattled like that until I lined the tray slot with some foam padding. It stopped the noise completely and was a cheap diy solution.
Had that same weird hum last year, did you check if the coils are clean in the back? Mine was full of dust and making all kinds of noise. I ended up shimming one of the front feet with a bit of folded cardboard because the floor was uneven. That got it to stop moaning for good. What all have you tried so far?