It may help your mum if she uses a walking stick or frame to help her and give her some support.
Hi,
Your mum should go see a doctor and get it checked out. I also fall down a lot because of my weird legs. If your mum has tingly or numb feelings she should go to a Neurologist and get it checked out. I also think that it will be beneficial for her to just go to a General doctor and just ask if there is anything else that could be causing her falls. An occupational therapist might also be helpful
I suggest to take your mum to see the doctor to get her blood pressure checked out, her ears and a blood test for anaemia and vitamin deficiency, especially the vitamin B group and her vitamin D levels.
Although she does have a narrowing of her spinal canal and pinched nerves that can cause balance problems, don't presume that her falling down is due to that.
Best wishes.