I am sorry your Mother is suffering from this. I had endromedtrial cancer that metastisized to my pelvic bone. After radiation, I had 16 rounds of taxol and carboplatin. The third treatment my feet swelled and I could not put shoes on to get home. It has never gotten better. This was October 2019. They tingle and wake me up burning. I walk on a walker and do not feel confident walking with it. It is starting in my hands. I feel so trapped and sad. I also had my pelvic bone removed and replaced with a 3d prosthetic, which has left me in constant pain. I wish I had something positive to tell your Mom. My doctor's have not really tried much, just collateral damage. Please forgive me that I am no help.