I have no idea whether these will be available where you are, bup, but in several European countries I’ve seen the Red Cross and Catholic Charities offer “caretaker relief” and “part-time caretaker” services (you do not need to be a member of either the RC or RCC to receive them, but there’s hoops to jump through). There may be something similar in your area from those or other non-profits. The Medical Social Worker should know.
I would really like to know more about that, if you have any links or resources to share. 
My daughter has worked as a care giver for several individuals while in college (for nursing). If there is a college near you, maybe contacting the applicable departments or placing an ad would be an idea.
(As an aside, last year she seemed to suddenly need more money. She had a job 4 hours or so a day helping a student who was in a wheelchair. Turns out he had turned 21 and his funding stopped. Although she wasn’t being paid, she kept working until he finished school. She is way too sweet.
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I don’t have any links- I know about it because my father does not need skilled nursing care , and Medicaid pays for 12 hours a day of home care. He’s authorized for 24 hours, but my mother doesn’t want or need an aide for 24 hours- she can provide some care, but she can’t bathe him, change him or transfer him between bed and wheelchair as she’s not young and has her own health problems.
Did your parents have to spend down some percentage of their assets to get help from Medicaid? I know that’s an issue with nursing-home care (there are exclusions to allow the spouse to not be completely beggared).
I have a friend whose mother is about to be moved into a Medicaid residential facility; she’s been in another, much nicer, facility for years but has depleted all her assets and my friend can’t afford to help, at all; the other has pretty advanced Alzheimers and really requires 24/7 supervision. Home care is not an option.
My father hasn’t had any assets in years and my mother’s assets are don’t matter as she exercised a “spousal refusal” which recognized in New York and a few other states. There was an issue with spending down income, but my father’s income now goes into a “special needs trust” , which is disregarded when determining Medicaid eligibilty. The Medicaid application was submitted when my father was in a nursing home and the requirements were the same for home care or nursing home care. However, the home care doesn’t cost Medicaid even 50% of the nursing home list price , which is $9000/per month around here.
Bump for bup!
How are you getting on?
While your wife may not be eligible for SSI there is another program - SSDI - which she possibly (probably) does qualify for.
I wish for all the best for you both in this difficult situation.