My wife has periventricular leukodystrophy. she got it at 59 and is now 60. life expectancy?

Are you sure of dx?: This is not my area of expertise in neurology, but are you sure it is periventricular leukodystrophy and not periventricular leukomalacia. The former is a condition usually seen in children. The latter is extremely common and is sometimes called small vessel white matter disease. Most patients with a western diet have some degree of this, particularly by age 60, and Aspirin is the treatment.