I'm saddened to read your post Dave, and I can't imagine how you and Marina feel let alone how your grandchildrens parents feel. I sincerely hope that the doctors are wrong or that some kind cure can be found or done, I really don't know what to say other than it's no fault of the family and everyone must stay strong for the children.
I hope you enjoy Xmas as much as you can and hope you all have the best Xmas present you could wish for.
Martyn
