When you have MM is lost of function in your legs and numbness a symptom?

My grandmother was diagnosed with MM about a month ago. Since then she has lost the use of both legs is bed ridden and is now has numbness in her right hand and foot. The doctors told her she would be back to herself in about a month. She has only had 2 treatments of radiation and her pain is unmanageable. She is 86 years of age.