Demand Physio and see what the Doctor says. He may say that it will not do anything for her, but at least you'll know for definite.
My very elderly Nan demands for everything she feels she genuinely needs from the NHS (especially Physio), and from the council, as she gets severely fobbed off by both.
Her mobility has really benefited from seeing a Physio, yet the Doctor was initially refusing. He has since apologised to her for not recommending it and agreeing with her, as he can see the progress she has made.
For me, I had issues with my pelvic floor after pregnancy and my Doctor wouldn't refer me for Physio, just printed off a sheet of exercises I could've printed myself. I did a bit of research and found that I could be prescribed a pelvic toner, which is often more effective than going to a Physio, and costs the NHS far far less. I went back to my Doctor and asked for a pelvic toner and she had no idea what I was talking about, so I showed her on my phone. She said they couldn't be prescribed, so I showed her the relevant information saying that they could and that it's cheaper for the NHS. She discussed it in a meeting and got back to me, with a prescription for my pelvic toner. It's been great. Be persistent.
If you don't ask, you don't get, and if you don't get what you want, then at least you get an answer that you can agree with or try to argue against if you think you are right.