Not sure what you're looking for here (if anything). Here, have some critiques on your construction:
Osias Witt, a 56 year old retired war time detective can’t forgive himself for the mistakes he has made, unable to find his families killer he’s turned to a drunken wreck, every night he would sit in his hotel room drowning his sins in a bottle of scotch.
This is a run-on sentence and not your only one. Also watch your comma usage.
A visit from an old man interrupts his thoughts, Osias asks him what the old man wants,
You use 'him' here twice, and each time it refers to a different person.
the old man explains who and why he is here and that he is here to give Osias one last chance
"who and why he is here" isn't parallel. Should be "who he is and why he is here." It's superfluous anyway - you can safely cut that phrase out, since you immediately go into why.
families
family's
the old man gives him one final chance
Repetitious. You've already said the man is there to give Osias one last chance.
He offers Osias’s soul and for his sins to be washed away
I'm confused by this part as it relates to Lucifer. These are not things normally offered by that particular entity.
I'd say take another editing pass at this.