I read this with great interest. We make the wheels for dogs and the GSD's most common problem is CDRM which is MS in dogs. It affects the rear legs initially and on a dog of this age it is highly unlikely that it would travel to the front but be advised that it CAN and that is to be avoided at all cost. I am one of Dogs Today's Dial a Dog advisors on CDRM and wheels. If this dog's rear legs are affected I could arrange a loan of a set of wheels, not of the type we make but these will work for the dog. You will find us currently on Ebay if you enter Dog Wheelchair and look for the UK company at the bottom of the listing you will see how to contact us. I have put hundreds of GSD's on wheels and they do great.