My Mom Was Diagnosed With Mysthenia Garvis A Year Ago.

My mom was diagnosed with Mysthenia Garvis a year ago. Then her antibodies were .72,after medication of a year antibodies came to almost 0. Some doc says keep on taking medicine while others ask her to do surgery. She is 54 and docs said they wont be able to do surgery after 55, so i am trying to find out does she really need surgery? If she doesn't need surgery then for how long she should continue her medication?