Benz diesels are very tough engines, if you are able to literally break the crank, you deserve a passing salute from a whole battalion.
Yes, if the block is fractured, dont overhaul that block, find a replacement one. You will be quite surprised to see that the lower rotating assembly is usually tip top or at max require bearings etc.
Take extra care to read the service manual atleast 3 times with a cup of tea to understand it, benz manuals are written quite cryptic and are usually this way to address professional repair people.
If a place says to use torque ratchet, do not andaaza it, if it tells to measure something, actually measure it rather than andaaza and eyeing it.