Answer

In my opinion, there is no prohibition. You prepare drafts for him at his request, and he decides what to do with them and when. And even if you know that he is a sinner, it is still his decision. This is not similar to a Nazirite who asks me to hand him a cup of wine across the river, because for the Nazirite there is nothing else to do with the wine besides drinking it (you could of course pour it out, but that is not a use). Beyond that, you are his employee and are supposed to follow his instructions. You certainly do not need to lose money (if they fire you) in order to keep him from committing transgressions.