My mother is 60 and at a normal weight. Is it normal for her legs to cramp, and for her ankle and foot to become swollen standing for a long period.?

Difficult to say. Although the cause of swelling and cramping is often difficult to figure out, i agree with your hesitation to accept that this is normal if her weight and activity level are also normal, especially if this started suddenly. Make sure her kidneys, liver, and heart are doing well. If so, often times a vascular medicine doctor can get to the bottom of this quickly - or at least reassure you.
No. Could be a circulatory problem causing a pooling of the blood and subsequent cramping. See a primary or vascular md.