It is actually very unusual for age spots to be itchy. Most age spots do not cause itch or pain.
There may be other causes for the itch including asteatotic eczema, which is eczema due to dry skin. This is common in the elderly.
Scabies, due to a mite infestation, hives and underlying medical problems can also cause itch in the elderly.
As the itch is bothering him for so long, I would suggest visiting a dermatologist/doctor to identify and treat the underlying course.
