Hormonal changes after menopause are major issue for skin conditions.The changes in progesterone and estrogen levels effects your skin and your skin might be thinner also drier and less elastic,its due to the oil glands that are less productive during this stage.
Using good quality moisturizer on your skin and regular use of sunblocks will help fight against the problems.Use skin care, and cleansing products which are more natural, without harsh chemicals that will further dry the skin.Use the products which have added antioxidants such as Vitamin C. These antioxidants help protect your skin from free radicals,which will make the skin age faster.
If the problem is serious talk to your doctor about HRT( Hormonal Replacement Therapy) and the skin changes he'll prescribe the favorable treatment for your mother.