Steve,
My thoughts are genuinely with you and your family.
I went through a very similar situation in April 2000 when I was diagnosed with advanced Hodgkins Lymphoma. It knocks the hell out you and you just don't know which way is up.
I sold my Contemporary Cobra for, I guess, the same reason as you, I just didn't know when or if I was ever going to be able to drive it again.
But I'm still here and the outlook is positive.
...and I'm now considering the prospect of buying and building a Kirkham.
I'm sure that many people have already told you, but a positive mental attitude does seem to make a very real difference.
I'm sure it all looks pretty grey at the moment, but when you have come out the other side, and I'm sure you will as I and countless others have done, you will be a much stronger person, both emotionally and spiritually with a fresh outlook on life.
By "spiritually" I don't necessarily mean "religious", but you will view life from a whole new perspective.
I now actually feel that my illness was a positive event and that I am now in a better position for having gone through it.
I don't know if this helps or not, but by all means PM me if you want to chew the fat some more. I personally felt that it helped me to talk to other about my situation.
Keep positive
Best wishes.
Paul