The IRS does not specifically state whether expenses for the care of an Alzheimer's patient are deductible, but they do provide information on how to make such a determination.
The primary factor is whether the lodging is essential for medical care. This can vary depending on the individual circumstances (i.e. how far an individual's Alzheimer's has progressed), so the determination must be made on an individual basis. See the information below for assistance making this determination.
Per IRS Publication 502 Medical and Dental Expenses (Including the Health Coverage Tax Credit), starting on page 10:
You can include in medical expenses the cost of meals and lodging at a hospital or similar institution if a principal reason for being there is to receive medical care. See Nursing Home, later.
You may be able to include in medical expenses the cost of lodging not provided in a hospital or similar institution. You can include the cost of such lodging while away from home if all of the following requirements are met.
The amount you include in medical expenses for lodging can't be more than $50 for each night for each person. You can include lodging for a person traveling with the person receiving the medical care. For example, if a parent is traveling with a sick child, up to $100 per night can be included as a medical expense for lodging. Meals aren't included.
Don't include the cost of lodging while away from home for medical treatment if that treatment isn't received from a doctor in a licensed hospital or in a medical care facility related to, or the equivalent of, a licensed hospital or if that lodging isn't primarily for or essential to the medical care received.
You can include in medical expenses amounts paid for qualified long-term care services and certain amounts of premiums paid for qualified long-term care insurance contracts.
On page 11:
Qualified Long-Term Care Services
Qualified long-term care services are necessary diagnostic, preventive, therapeutic, curing, treating, mitigating, rehabilitative services, and maintenance and personal care services (defined later) that are:
Chronically ill individual. An individual is chronically ill if, within the previous 12 months, a licensed health care practitioner has certified that the individual meets either of the following descriptions.
Maintenance and personal care services. Maintenance or personal care services is care which has as its primary purpose the providing of a chronically ill individual with needed assistance with his or her disabilities (including protection from threats to health and safety due to severe cognitive impairment).
On page 12:
You can include in medical expenses the cost of medical care in a nursing home, home for the aged, or similar institution, for yourself, your spouse, or your dependents. This includes the cost of meals and lodging in the home if a principal reason for being there is to get medical care.
Don't include the cost of meals and lodging if the reason for being in the home is personal. You can, however, include in medical expenses the part of the cost that is for medical or nursing care.
Note that any link in the information above is updated each year automatically and will take you to the most recent version of the document at the time it is accessed.