How do you make this assumption? If his car is 100% stealership's fault and can be proved to be the stealership's fault, then stealership will be liable. Instead of searching for an engine the OP should raise the case with BMWNA and contact a lawyer.
However read the notes on the workorder. It says "Customer will perform fix later" Which means the OP elected to fix the "major oil leak" later knowing that it will cause issues. I can only imagine the SA's frustration telling the OP to fix it but the OP refusing. Knowing the issue is there, that it may cause issues later, and that the work is recommened but refused....would all make the OP negligent not the stealership. Eitherway, knowing that the OP refused to a fix a major issue, my recommendation is to send the car to a reputable shop and do it the right way.
