Walter White's mother is never seen in the show, although she is alluded to several times. Walt's wife, Skyler did not get along with her mother-in-law. During the events of Breaking Bad, she lives somewhere far enough away from Albuquerque as to justify having to fly to visit.
After growing suspicious about Walt's behavior, Skyler called his mother to see if he'd been getting money to pay for his treatment from her and found out that Walt had not told her that he had cancer, nor had he been to visit her. ("")
While talking about his father, Walter said how his mother was terrified that he might suffer from Huntington's disease too and got him tested. When his father was dying, Walt's mother would take him to the hospital to visit and try to keep a positive attitude. After his father's death, his mother would continue to tell Walt many stories about him. ("")
- She is never mentioned to have died during the series, so chances are she outlived her son.