How do you handle mother-in-law who is negative and delusional?

My 89 year-old French mother-in-law came to live with us in California two years ago. It has been a living hell. My husband is an only son who was raised by his single mom from the young age of 2. She never remarried after the divorce. She speaks little or no English, does not hear without hearing aids yet often neglects to wear them, is legally blind (macular degeneration), and has some form of dementia or Alzheimer's. My own mom passed away with heart condition/lung cancer at 65. MIL is a smoker, and even though she smokes in the backyard, I can still at times smell the cigarettes/fumes.

She constantly complains to us about her vision impairment (I understand that it is very troubling to her but her vision loss occurred before moving here) and a host of other ailments including foot pain, hearing difficulty, skin problems, lack of sleep. She talks incessantly about washing machines that neighbors are running all night that keep her up, yet we live far away from any other houses. She heard these same noises back home in France - I don't know if the noise she is hearing is tinnitus or delusional.

She also loses things and blames others for stealing them - it can be a comb, bras, bathing cap, soap - or even her cigarettes. She has accused my son and his girlfriend of theft on many occasions, or the cleaning people. She is obsessed with this and mentions this thievery issue multiple times during the day.

She yells all day long and my nerves are completely frayed. Right now, I am looking for work and am at home a lot, so spend proportionately more time with her than my husband. I feel very depressed about the situation. My husband is a manager who works 50 hours a week. All this is especially difficult, as I had a traumatic brain injury several years ago leaving me with chronic headaches.

She has been a difficult MIL, very controlling and negative, very attached to hubby, and hyper critical of the kids. My dad is also quite challenging too in terms of constant complaints and chronic hypochondria, and calls me incessantly. But at least he lives on the East Coast and has financial means to have home assistance (plus I have two sisters who live close by).

Further, it is difficult finding resources to help, given her communication problems and lack of English. Though she visited every summer, she has not adapted well to life here. She has no real activities, and I am working with a local day facility to see if she could try it out for a couple of hours and see if the language is not too difficult a barrier. I found her a lovely native French speaker to come by the house twice a week to teach her a few English phrases. We both take MIL to doctor visits.

She cannot be on Medicaid for another 3 years and neither she nor we have the financial means or long-term insurance if she ever needed more skilled care than what we could provide at home.

My husband is an absolute saint on many levels. He was very insistent that because she could no longer live at home by herself, that it was his obligation to take care of her. And I guess me, by default. He does so much for the family and is trying to make everyone happy. Though he pretty much told me that between me and MIL, I was the one who had to go if I weren't happy with the situation. That is due to the fact that we couldn't send her back to France. Though he still loves me and I feel the same.

I feel that hubby is in denial about her dementia problems and how much a toll it is taking on me. He told me that I have to change the way I take her, ignore her, etc. But with her ranting and yelling within earshot continuously throughout the day, it's no easy task. Her behavior seems better in the evenings and weekends when my husband is home. My hubby doesn't like emotional topics or confrontation of any kind and would rather sweep all of this under the rug. But this is definitely wearing on our marriage and our physical and emotional health.

I would appreciate any advice about handling this situation or available resources out there. Would meds help her behavior? Hubby has never discussed these issues with her internist, but I am encouraging him to do so on her upcoming doctor's visit. We live in a smaller town, so do not have access to a lot of French people or things - we have tried to find a French-speaking caregiver through local agencies to no avail, so it is hard to get away from the house for overnight. Son in late 20's lived at home for short time, and moved out because of he could not handle her accusations. So he is not a viable option for caregiving.