I am so sorry to hear about your injury, that REALLY sounds painful. I think there are a lot of factors when deciding how to proceed with his training, during this time.
First, Has your puppy been to a puppy socialization class yet? It is super important for him to be able to socialize with other people and dogs during this time period. Do you have the ability to continue allowing him to socialize while you are recovering? this is probably the most important thing to think about, in my opinion, because an under-socialized doberman can be no fun.
As far as training goes, you should be able to do a lot of it from a resting position. I am guessing you probably aren't to busy while you are recovering so should have lots of time to teach him all sorts of fun tricks. Even if you aren't teaching him basic obedience, by teaching him various tricks he is still developing the ability to learn things, more easily, in the future. Heck, I would just sit in my chair with a clicker and bag of cookies and shape all sorts of behaviors from things he just naturally does. At this age they are so receptive to training that it can be a real riot to see what they can learn. Here is a video of a 14 week old puppy that I rather enjoy.
Fiona 14wks- Service Dog In Training - YouTube
Obviously you cant teach all of these behaviors due to your injury, but it gives you an idea of the brain power you could harness.
The only other concern I have would be teaching your pup to walk nicely with you. With your injury, an 80lb beast pulling you around could cause trouble, even down the road ( I assume). It is so much easier to teach a polite walk when they are smaller. That said, its not necessary and can be taught at any time (just may require more muscle at an older age).
I dont think you will cause any real, irreversible damage, by not engaging your pup in formal obedience training, at this point. I would suggest still teaching him things that you have the ability too, and you could even work on things to help you while recovering. Some ideas might be, to retrieve dropped or desired objects, help you take off your clothes (I taught my pup to pull/hold the corner of a piece of clothing to help me take it off, like a sock, pant leg, arm on my coat, etc.), open/closing doors, etc...
The only issue I see is the potential for lack of proper socialization. Are you able to drive or have someone else drive? Could you possibly find a trainer that works with maybe a dog daycare that he could go to a couple times a week and then pay a little extra to have the trainer work with him, on those days, for you? or maybe you could hire someone to stop by and walk him a few days a week or take him to a puppy socialization class for you?
