Rollator (Ashfield CA14)

My frail sister doesn't walk because she no longer feels safe on stick and a zimmer is difficult. Would love to get her a rollator of some sort so she can become a bit more mobile. An ideal one would fold and have a seat, but ANY type would be an improvement on her current situation. Pls can anyone help? As long as it's safe to use and the wheels turn, the condition doesn't matter.