Sorry to hear about your condition; that must be painful.
On the 782 at auction, as you probably know, it doesn't matter what a fair price is, it's "what are you willing to pay out and be happy" --that is the issue. You're not dealing with an owner here, but perhaps 2 or more other guys all wanting to
be the new owner. That scenario can blow "fair" right out of the water...
...then again, you might be able to pick it up for cheap if no one else is that interested. That's why we go to auctions, isn't it?
Like others wrote, if you don't know any particulars, it's difficult to say what is a fair price. Hope you're feeling well enough to attend and that you win the bid.