This sounds like a nursing home or assisted living. No clue why wife felt necessary to tell what "future personal plans" had being brought up in the work place at all.

Just from the minute info given...    At the least this place is probably out of state compliance. Does Wife have power to hire or fire? if so (or not) did she make any attempt to ask for proper staffing? 

So far the supervisor has proven to be a 1st class idiot.

Created a hostile work environment, threated to fire for poor performance, then reiterated Wife Has been doing job "there is no way I am going to fire you and let you sit at home and collect unemployment-. "   Catch 22,, won't fire, creates hostile work environment to get wife to quit. DO NOT QUIT!  Supervisor reduced work force to make a situation where Wife could NOT "do her job" by filling in for nurses/med staff. Demanding date for quiting,,, more harassment..

When wife goes to work tomorrow,, she should not say anything about ANY quitting date. Supervisor throws a fit,, so what,,?    Wife needs to document everything, what, where, when, who, how.  THAT MEANS LITERALLY EVERYTHING !!  including any witness's.

What happens or doesn't happen on the farm should stay on the farm period. Whenever this harassment started or as far back as can be remembered everything should have already been documented.  DO NOT use 'office supplies' OF ANY KIND, nor Co. computer to keep records on and take all documentation out of the work place. PERIOD !!

As stated sounds like state regs. are NOT being followed and wife needs to get a sheild in front of her, otherwise you can bet this  (ahem)  Fine Establishment will throw her to the "state Wolves" in a heartbeat.  She has got to follow her employee handbook (if there is one,, which doesn't sound like there is much of one)  and/or her job description and when that is deviated from she also needs to document the reasons why. If her supervisor tells her to that needs to be documented too. If she steps in to fill in for staff because there IS NO staff, she needs to document that too !!

If this nursing home is that far out of compliance,, wife should feel enough duty to the residents to report the place to the State. It can be done anomously, and she should NOT give information out that only she would know. (Common knowledge stuff is impossible to prove)

IF wife is terminated and or quits at this point in time, she will likely not ever find another job in that field regardless of How badly she may need it. Long as she sticks with it and does the right things, the State Labor Relations board (whatever it's called in Ks..??)  will side with your wife.

IF it were me, I would get a good Excellent labor attorney and keep a daily documentation on everything that happens at work. who,what,when,where,why,how,..

This sounds like it has balloned into a complete Charlie Foxtrot, and I would make sure that when I did walk away a few things would happen.  Supervisor would be fired, Company would be liable for damages, and Especially the people who are the most vernerable are taken care of properly not what's cheapest !  Which sounds like is happening now.  

I've got a parent in assisted living care. And,, I've had to move her a couple of times. 1 place,, I turned the "alc" into the state governing boart 3 times, and got the "alc" finded with a letter in their file, ALL 3 times. I will NOT put up with that krap for 20 seconds.

BTW.. you can Bet all those soybeans the "boss" is writing up all kinds of documention on your wife and it will NOT be pleasent. WIFE needs to do excellent documentation.