I'm worried about mom's mobility. Any tips?

Mom was diagnosed with lung disease over a year ago. She now is on oxygen full time. 8 liters. Here recently she has been so sick. I took her to Dr and she had UTI. She felt better, and stop taking them so now she feels sick again. They gave her new Rx and said to complete the antibiotics. Mom has history of falling, and now she can barely get out of chair and says her legs feel like they are giving out. I'm just worried. I'm getting her a walker next week but with this long disease I just think I should have home health come in weekly cause they can recognize symtoms that need attention faster than me. Any tips to get her to agree? I've had them come in before, but she always calls and tells them not to come back. I need some extra assistance for sure. Raising teenage son,full time college student and mom's caregiver so a lot on my plate!