The disposer died on Thursday. After performing manual rotations using a wrench, it still didn't re-start and I gave up. I tried again before going to bed and it started. I thought it was fixed. It was still running when I checked Friday morning.
Friday night, Gumby washed dishes then drained the sink after finishing, and water flowed out from the cabinet under the sink.
So here I am, on Saturday morning buying a new disposer. I spent the late morning/early afternoon installing the new disposer.
I still need to figure out what to do about the cabinet. The pressboard sagged; all the water-logged cabinet parts need to be replaced.