Complex sentence: While Karol has lost his wife and his property, Mikołaj is married and successful, he offers Karol a job consisting of killing someone who wants to be dead but does not have enough courage to do it himself.
Split into simpler sentences: While Karol has lost his wife and his property, Mikołaj is married and successful. Mikołaj offers Karol a job killing someone who wants to end his life but does not have the courage to do it himself.