The Parkinson Foundation (parkinson.org) has a nice publication called “Caring and Coping.” Though the booklet is published by the Parkinson Foundation, there is not much Parkinson’s-specific about the publication. You can find the publication (PDF) here:
Included in the “Caring and Coping” booklet is a useful worksheet on questions to ask an agency during the hiring process. The worksheet says:
Hiring someone to take care of your loved one is a decision that must be made with careful consideration. There are many questions you can ask to make sure the agency can meet your needs, as well as questions to make sure the agency and its employees are competent and have the proper training, licensing and insurance.
Here’s a link to the list of questions to ask the agency: (the worksheet’s title is “Questions to Ask a Potential Paid Agency Caregiver,” but these are really questions for the agency, not the individual aide)
And here’s a link to a related document, an “Action Plan for Hiring In-Home Caregivers,” which gives the suggestion of writing up a job description: