Hi VinnyL, We don't have a grey yet, but are planning to adopt once our beloved 20 year old kitten passes on. We've been trying to educate ourselves on everything there is to know about greys, and in doing so, I came across a pdf article on one owner's experience with her grey's serious corn problem.
I think that if the ex racer we adopt ever develops corns, we would try the treatment explained in this pdf link before considering anything more invasive (such as surgery, which unfortunately does not result in a cure anyway). This treatment is not a cure either, but it seems to have given the owner some confidence, as well as confirmation, that her grey is beginning to enjoy life again; not to mention relief that his corns are at least manageable. Here is the link:
http://www.steelcitygreyhounds.org/downloads/corn.pdf
Are your greys a pair bond? I really hate to suggest this, but If they are not, there is the option of surrendering one, so that both dogs' needs can ultimately be met. Such a heartbreaking position to be in; I feel for your family and hope that you will not have to choose this option.
Hopefully, an experienced corndogger will chime in with sage advice for you.