Hi! I don't post here much but I read your post and I wanted to offer you support.
Its been almost ten years since my car accident. It took six months to get diagnosed! I was even living in Minnesota at the time and yet all the idiot doctors couldn't figure it out when Mayo Clinic was five hours away! Literally my tbpi was diagnosed by a physical therapist. That's when the the US insurance and legal system screwed me over for life... I have never seen a specialist and I can not get health insurance because my arm is now a pre existing condition. If you can get a second opinion do so. Even if they say nothing can be done at least in your head in the years to come you will know for sure you did everything to try and fix your arm.
I remember the first six months after being diagnosed very well... The pain was so bad it hurt to even breath. The doctors were speaking a foreign language. All I found on the internet was doom and gloom. Seriously it was awful because know one understood! I heard, "Its just an arm!" so much I wanted to box the person's ears then tie up their dominate arm for just one hour and see how well they could survive. A wonderful lady was my saving grace. She herself had this injury. Every morning she sent me an email for months. Those were the months I did not want to move! I only moved because of my kids.
Bluntly put at this point you are stuck in between shock and grief. Everyone goes through it and for different periods of time. Next stage is depression/anger by the way. Over the years I have noticed the patterns. I also notice that everyone of us at some point say, "Screw it." That is when we all figure out how to reclaim our life even if it is just one thing. That is also when we either try to figure out a way to fix our arm or we just ignore it.
As to healing and all that doctors have only a small clue as to what is "normal". I was over two years out before my arm even showed any sign of life! Advances are happening in medicine that I think will help find a cure for all types of paralysis.