I am glad that you have Toby to help you! Don't feel guilty about his fall -- Toby's breed is meant to get into some mischief (and that is why we love them!) I hope that you can make him a wheelchair... if you can't afford it try calling a Lion's club near you...or other charity organizations. Explain the problem and how much you would need for a chair for him. Or call a local hardware store...they may help also. Then you can take Toby for walks again -- and if you are near a school or hospital, maybe you could take him to meet the kids. For some reason, kids can relate to an animal that is disabled better than the can with PEOPLE that are...and it begins to open their minds to accept that everyone is different.
Have you thought about training Toby to be your service dog (even in the wheelchair)? You can email me -- vsgentilman@bellsouth.net if you are interested in more info.
My husband is bi-polar -- we have been married almost 38 years. He uses Hannah, our Great Pyrenees, as a service dog. She helps him pick up things (he also has a bad back), bring him things, and she does a wonderful medical alert for both his blood sugar and his mood swings. She is a huge help for him...especially when he is a bit unsure of a situation. He knows that he must stay level headed because she would react like a Great Pyr does...go into protection mode. THAT is not allowed in a service dog. smiles!
Hang in there...