Great Danes’ weak points are their hips. Standing on three legs or three legs and a prosthetic may be viable for Jack Russell, but the chance for success with one these big fellas is not good.
They also only live 6-8 years at best. I have owned four of them in my life, and their short lifespans make them real heart breakers.
All said, it may be time to let the dog go.
I have had 3 Danes now, my last went at 9. I rescued this Dane at 7mos. I talked to The great dane rescue I got her from this morning and she has some that go to 13 and 14. It is usually a short lifespan. I am hoping I have one of those this time.