Electrical Fault 2016 Prostar

Hello guys, Heavy D, if you are out there this is for you! I have a 2016 Prostar with the ISX15 and Eaton 10 speed Auto Trans (Push Button). The truck batteries were low and there was a very slow crank. I hooked a jump box up and still had a slow crank or a low voltage/amp crank. The engine would slowly turn over but not fast enough to fire. After trying several times, the key was left in the crank position for too long resulting in an electrical fault along with ABS module message coming on in the cluster message center. When this happened, the truck will no longer turn over. The batteries were changed, all fuses/relays were checked but still no crank. Truck was scanned, there were codes that made no sense, for example output shaft speed sensor, The codes would clear but come back within 3 seconds using a scanner. The Batteries have been disconnected multiple times over about a week, trying to reset the modules, with no luck. (Electrical fault still shows up) The truck will start if you jump the starter, however the transmission will not engage. The "DRN" (Drive, Reverse, Neutral) only flashes when pressed. I believe the low voltage crank corrupted a module or fried a module, therefor the truck does not know it is in Neutral, therefore it will not crank with the key. I had the truck towed to International. I gave detailed notes of what was going on, however the tech never read them, therefore, spending 3 hours and coming up with a bad starter.........No, it's not the starter, it starts if you add 12 volts to the solenoid, and the transmission doesn't engage or read......After updating him, he says there is not any communication with the TCM. They want another 4 hours to check power and grounds before replacing the TCM. They say there is only 1 TCM in the world and it's in Canada at $5,000 plus $200 for shipping + install and programming and is 2 weeks out. Whoooo Saaaawwww!!!! Question is: Do you think that the TCM itself is fried, electrical issue in the wiring/connections, or is there something else to have checked?
Also, The dealer was able to find someone to build out a new TCM, however they want 8 hours to R&R the TCM. Does this sound right? From what I see the TCM is just on the side of the trans with a few bolts and 2 connectors. Thanks! Thank you in advance!!!!