Hello,
I apologize for the delay. This case is likely too complicated and difficult to provide much assistance via text.
In all of these cases I think it is best to contact as many local rescues and pet care providers as possible. This might mean reaching out to your local shelter and veterinary college. You can also start a go fund me page. Post on all social media accounts and personal accounts. Start with general practice vet who the rescues recommend. Give them a realistic budget for you. Ask about payment plans and payment plan companies like care credit or vetbilling.com. There are places to help. Keep trying and keep asking.
Not a vet, but someone who was heavily invested in Doberman breed education. We see this a lot in Dobermans fed puppy diets (not large breed puppy_. What are you feeding, and is it an adult or All Life Stages food? Have you consulted an ortho vet?