Who is Alison Mayhew from One Day and what is their importance?

Alison Mayhew is the wife of Stephen Mayhew, and mother of Dexter Mayhew. Alison is described as a drinker, but also as a wonderful, caring mother. Alison counsels her son, telling him to make sure his life is on track, and advises him that he should go for Emma. Alison contracts cancer a few years into the book, and later dies. The loss is felt deeply by Dexter and Stephen.