Re: so ladies II…
Good question!
In some professions there is “an old boy’s club” and there is an expectation that you take clients out for socializing. The nature of socializing differs from one group to another and from one set of clients to another.
The easy answer, is no - strip clubs are a no-go - that’s going too far and I think that’s a line you can easily avoid crossing. But, I’ll be honest, the “line” is different for different people. Bars or resto-lounges that serve alcohol - that doesn’t bother me, but for others that’s also a taboo. And truth to tell, have you seen the clothes the waitresses don’t wear at some of these places? 
So then does it make me hypocritical saying, strip clubs = not kosher and bars - well that’s up to the person?
And okay, here’s another one thrown into the mix. We have some amazing upscale restaurants here in town and there’s one that’s a offline betting bar/restaurant. Given that people gamble there, is that taboo as well - the client can gamble, and yet you choose not to or even taking the client to the race track - kosher or not kosher?
And not to turn it around and answer a question with a question, but what if it’s the wife who has to take the clients out? Kosher for her or not?
Question is what does he want to do? What does his conscience tell him is right? If he is willing to go to such an inappropriate place for some extra money - well then I would think less of his judgment and values.