Re: Shrinking Vigina ?
Yes, to answer your basic question, there are "vaginal dilators" which are used to help well, "stretch" the area. Some are medical in nature - like what the doctor used, and sometimes they are prescribed for use at home.
This problem can occur because of menopause, from the muscles atrophying from lack of use, after surgery, from chemo, etc, etc. So, yes, this is a real medical thing. However, if you look up pictures of them, and thinking about needing to have a doctor do that, I'm sure you might understand why your wife didn't neccessarily want to discuss this in great detail. It's probably kind of embarrassing.
Generally, this procedure goes hand in hand with some kind of hormone therapy, to stop it from becoming a recurring problem - so, if she hasn't, she might want to talk about that as well. (Or think about a natural alternative like - Estroven or whatnot.)