I know someone who recently started a burrito restaurant and now wants to get help from/partner with/get funds from/etc. his cousin who runs a night club (it's not a strip club or anything like that but a regular bar/club whatever where people go to drink and dance to degenerate music, still a den of immorality of course) and who also brings all kinds of bad singers and bands into the country and organizes concerts for them etc.
I firmly believe these businesses his cousin has are immoral/dishonest, but I was wondering if it would be wrong in his case to team up with this person and use his (in my view) dirty money to expand his own honest business. I personally know these people. His cousin actually offered to invest, he didn't seek him out.
I don't see how it would be lawful to team up. You would be forced to give publicity to his own dirty business and of course endorse it, since they will be endorsing you, and who knows what else may happen down the road.