The worse case is that if it can't be rebuilt. If it spun a main bearing that would be the case. If the crank was not repairable it would almost be the case.
The problem is that the car is only worth about what a rebuild is worth. not too bad if the labor is free. A used motor would be a lot cheaper way to fix it.
Bosch Master, ASE Master, L1
33 years MB technician