My wife gets terrible migraines. Out of the blue, she suddenly feels faint and nauseous, very sensitive to light and noise, and in extreme pain.?

Concern. New symptoms may suggest a diagnosis other than migraine. A neurologist or internist would be a good place to start.
Talk to physician. Migraines can be very debilitating when they occur. If they happen relatively often, a preventative medication is sometimes helpful. If they are infrequent a migraine pain medication can be used. Also, migraines can have a variety of triggers, so have her keep a headache diary noting both when, and what she was doing, previous ate, etc. Then she should talk with her doctor about the best approach.