For in-home caregivers, you can deduct the cost of nursing services. The services do not have to be provided by a nurse but they must be the kind of services that nurses usually provide, such as providing medication, checking vital signs, changing dressings, and assisting with grooming, bathing, and using the toilet. Assistance with other home services, such as cleaning and meal prep, is not deductible. If the caregivers provide both nursing and non-nursing services, you will have to determine a reasonable allocation as to how much of the cost is nursing services. See publication 502.
https://www.irs.gov/forms-pubs/about-publication-502
Separately, if you pay more than $2700 per year to someone who works in your home, they may be your household employee. If they are, you must withhold household employee taxes, pay those taxes as part of your tax return, and issue them a W-2. See publication 926.
https://www.irs.gov/forms-pubs/about-publication-926
In some cases, the home care worker might be a self-employed person acting as an independent contractor. In that case, you can pay them cash and don't have any other obligations. The determination of who is an employee and who is self-employed depends on the nature of the relationship, and who has control over the time, place and manner of the work. The IRS has more information here, and you may want to have a discussion with the caregivers about how they want to be treated. There can be severe penalties if you treat someone as a contractor, and they file a complaint and the IRS later determines they should have been treated as an employee.
https://www.irs.gov/businesses/small-businesses-self-employed/independent-contractor-self-employed-o...
If you determine the caregivers are household employees, and you pay household employee tax on your tax return in addition to the wages, those taxes (or a portion of those taxes) are also allowable as medical expenses in the same proportion as their services count as medical expenses.
