I was very afraid of heeling, to the point where I was uncomfortable. My poor husband could not even use the head since I was afraid to get behind the helm.
I took the ASA 101 course on basic keelboat this summer. Now I am always behind the helm. My instructor taught me more in 3 days then my husband in 2 years. He knew my fear of heeling, and got me to single hand the boat in 25 knots of wind for 5 hours. Amazing what you can do when you reef (something my husband didn't understand).
Have your wife take a course. It is the best thing.