Dad-E-Wagon

Greetings and happy holidays to all fellow members.
This is my first post and I'm hoping someone has some insight on this headscratcher. My '06 E61 530xi was in a rear end, front end collision in October. The car that hit us pushed our car into the truck in front of us, the front impact was minor compared to the the back. The car performed as expected, no airbags, battery safety terminal blew, flashers turned on and engine shut down, would not re-start, would not crank (due to BST). Car was towed and the flashers ran the battery down while at the yard. Upon reaching the body shop the battery wouldn't take a charge, I'm told the body shop tried starting the engine with a jump box when it first arrived and got slow cranking but no start, so it and the BST cable were replaced, car still wouldn't start. BS (Body Shop), called my Indy shop and they suggested bad starter, car sat while we worked out issues with insurance, that's another story unto itself. Car was just towed to Indy shop this week, they replaced starter and still no start. Deeper investigation showed a real mystery, the engine timing was apparently almost 180 degrees off of normal. At this point Indy shop is looking deeper for causes and downstream damage but we have zero explanation for how the timing would be so far out of whack without any apparent influence besides the collision. All scenarios discussed don't reveal any direct influence on the valvetrain.
I can see how a heavy rear shunt can act on things like exhaust piping, and manifolds, engine mounts, and other "external" engine components. With the vehicle in Drive, with my foot on the brake, it seems unlikely the impact should influence internal engine conditions, esp. timing. I know the driveline takes an impact and can route torque back through the axles and linkages, but it seems quite a stretch to see the influence come all the way back through the axles, driveshaft, transfer case, gearbox, and torque converter. The vehicle being at rest and in Drive should mean that the torque converter was decoupled from the engine, preventing the shock from reaching the crank and any upstream connections.
So, this is where we are now. I've been struggling, kicking, scratching, clawing and biting to get the insurance companies to cover the cost of the body repairs, which have ballooned to around $9000.00. I finally caught a break and the other driver's insurance, though 40 days late to the game, stepped up and offered to cover the repair, pending the preliminary mechanical evaluation. Now I'm asking the community for a "Christmas Miracle", for some insight into the solution to this conundrum. I cant bear to say goodbye to my unicorn. Your help is most appreciated. Thank you all for your participation on this forum, it is a valuable asset to all drivers and enthusiasts.

Kind Regards, and Best Holiday Wishes to all fellow BMW fans.

John E. AKA "Dad-E-Wagon"