I guess I'll address the elephant in the room...
Why did he start taking the pump assembly apart with the tub still full of water? The drain pump was obviously not an issue.... I'm surprised that didn't annoy anyone else.
I've never seen a self-cleaning filter/chopper dishwasher that bad. A filter machine, yes, most certainly. I doubt that machine has ever been disassembled in its entire life. It's amazing the variation between people that don't rinse dishes but know not to leave copious amounts of waste on them, and then the people that think you should dump the rest of the chicken stew in along with the pot.
My aunt on my dad's side (the one I'm not as fond of) has a GE with the filter. She's called me twice in the last year or so because the dishwasher won't clean, and will sound like it's choking on air. Both times I've cleaned and disassembled it, there's been the grossest goop caked on the filter and in the perforated bell that the filter sits over. She swears that she uses the Heavy cycle with Heat Boost, and sometimes the Sani-Rinse. She also says they scrape dishes, though the consistency of some of the stuff in the bottom is like stringy chicken pieces or almost dissolved noodles. I've tried to coach her into making sure that the only stuff left on the dishes is what can be melted and dissolved with hot water; if it's solid bits, get them down the sink drain.