As long as the story makes sense
...and for the story to make sense, such that we really get into it, it has to be at least somewhat realistic, at least in the world in which it's set. Heaven's Door is set in a specific place in the United States, some time in the late 2010s or the 2020s (based largely on MC's car). So it needs to act like it, or at least "close enough."
And of course there are some allowances. Most notably, every attractive woman we encounter is irresistibly drawn to MC for no readily-apparent reason*--just like in every other AVN. It's a trope of the genre, and we hand-wave it away. But the more we have to do that, the less the story makes sense. If we just want a story as an excuse to get from one sex scene to another, this doesn't matter too much. But if we want to immerse ourselves in the story, there can't be too many such issues.
So, on the premise of the story: it's kind of shaky. At least from what I know of strippers and strip clubs (which is very little, and I'm just fine with that), "stripper genuinely falls in love with a customer" is a pretty rare thing. Like, something that would make unicorns look commonplace. Two strippers doing it, and each being OK with the other? That's really stretching. That they'd both do it almost immediately after meeting him? It does fall under "everyone wants MC," but it remains a bit of a stretch.
When it comes to the "treatment for MC" question, I'm entirely open to it--though I'm not a medical professional of any flavor. I know conditions of this general sort can be treatable, in many cases with very positive outcomes. The game/story even tells us it's treatable, through both doctors who talk with him about it. So why isn't MC getting treatment? I guess I'll have to wait and see, though I'd suspect it has a lot to do with what he encountered immediately after getting his diagnosis. But if we hear that MC's decided to pursue treatment, and in due course that it's been effective, that wouldn't so much as raise an eyebrow for me.
* Sure, even by the end of Ch. 1, he's given them some reasons, but Nikki and Patricia fell for him with just one evening's hanging with him in the club, and Pixie apparently with even less than that. And I'm sure it doesn't hurt that this MC actually looks like an adult.
