92 yr old mother residing retirement facility receiving "assited living" services which are additional costs above/beyond rent for lodging. Lodging cost tax deductible?

Medical expenses are deductible.  Medical expenses include nursing services, even if they are not provided by a nurse.  Nursing services include assisting with eating, bathing, dressing, taking medications, and so on. 

Assisted living expenses are not deductible medical expenses.  That includes the cost of rent, food, laundry services, activities, transportation, personal companionship, and so on.   (Note that if a person is in a nursing home because of a medical condition, the entire cost is deductible and you don't have to split out medical and non-medical costs.  Assisted living is generally a level of care below a nursing home.)  If the assisted living facility provides some nursing or medical care, you can deduct that portion of the costs.  The facility should provide a breakdown for you. 

However, assisted living can be fully deductible if these conditions are met:

1. The person has a medical condition or disability that is permanent, or will last at least one year, or is expected to lead to death.

2.  The person requires assistance with 2 or more activities of daily living, or has a cognitive impairment so they would be a danger to themselves or others if left alone.  (Activities of daily living are eating, bathing, dressing, toileting, transferring, and managing incontinence.)

3. Their care is provided according to a written care plan developed by a doctor or medically qualified social worker that is reviewed and updated at least annually.

If your mother meets #1 and #2 but doesn't have a written care plan, talk to her physician or the facility about preparing one.