2006 CTS batterie died, now will not turn on
 

Hi all,
My 2006 cts screen showed charging system need service then a few days the battery died. Unfortunately I was traveling outside the US when it did and had to count on someone to take a look and take it to the garage.
They were able to charge it and back it up out of the parking port. When they took it to the mechanic he couldn't start it even after charging the battery. He said its the timing belt.
my question since we were able to charge the battery to get it out and the battery probably died again if it could be related to the key brogrammin being lost? If so can I reprogram the key?
I only have they key, no fob or wireless remote.