You usually do not need a prescription to buy a walker or rollator since most medical supply stores, pharmacies, and even online retailers sell them over the counter. That said, it may still help to talk with his doctor or a physical therapist because they can recommend the safest type and make sure it’s adjusted properly for his height and balance needs. Honestly, a lot of older parents resist walkers at first because they associate them with losing independence, even though they actually help people stay independent longer and avoid serious falls or hip fractures. Sometimes framing it as something that helps him stay active and keep moving safely works better than focusing on weakness.
I got most of my references here:
https://hopebridge.care/why-mobility-aids-matter-for-senior-independence/
https://en.wikipedia.org/wiki/Mobility_aid
https://www.healthinaging.org/tools-and-tips/caregiver-guide-mobility-problems