One more peice of advice I'd add. After or during trying all the above advice, if you still keep having what you feel is an irrational fear of healing. Go get or rent a small sail boat on a windy day. Strech full canvas so to speak, put your life jacket on and try your best to flip the sucker. Keep trying till you do.
This will help in two ways. First you'll find how much it takes to flip a sail boat over. Second you'll find that flipping over isn't the end of the world either. It's along the same line as getting back on a horse that has thrown you, or getting back on a motorcycle after a wreck. except that you forcing the wreck.
Maybe I'm missing some cryptic message with your suggestion Dan, otherwise, I simply can't agree with this approach in overcoming a fear of "healing" (heeling - ironically).
Keep in mind that Lucy is in her mid-50s, not a pre-teen Opti-sailor. Advising her to "flip" a small sailboat deliberately, cannot possibly alleviate her fears of a knockdown on a larger keelboat.
On the contrary, I believe it will only amplify her fears since as most sailors know from experience, small sailboats, such as centerboard dinghies, are very tender and will go over easily without crew ballast. This in no way can be comparable to the size sailboat her and her husband are considering.
Could you possibly expand upon what your intent is with this advice?