I will be down in November and someone in my group will need a walker. Heard there is a place to rent them. They will be staying on Dutch side for one week.
Dr. Deketh, behind the Maho Pharmacy, used to rent a limited supply of wheelchairs and crutches etc. We rented a wheelchair from him a number of years ago. It would be worth a call depending on where you are staying. https://www.mulletbayclinic.com/about-us