Perhaps the fact that I find this whole line of thought a little befuddling means that I shouldn't be answering the question. But maybe if I explain my confusion, that will help.
Start with something simple. I might be curious about, say, some abstruse mathematical claim. And so I go to my mathematician friend and I say "Is it true that such-and-such?", where "such-and-such" is the mathematical conjecture I'm interested in. It would be pretty odd, wouldn't it, if my mathematician friend waxed "philosophical" about whether knowing the answer would change my behavior. In one way, of course, it would: I'd stop asking the question if I knew the answer. But in most other ways, life would go on as before. And yet, I still want to know whether such-and-such is really true.
The point is that there really are two issues here, and it seems like confusion to mix them up. One is the matter of whether what I'm curious about is so; the other is the matter of what I'd do if it were -- or weren't.
Now the two are related, of course, but the thought offered by Mr. K seems to get things exactly the wrong way around. If my behavior would be significantly different depending on which way the answer turns out, then knowing how things really are is what I need to figure out how best to behave.
Suppose I want to know whether my (hypothetical!) rich uncle who has just died left me a fortune in his will. If the answer is yes, I can assure you that this would make a very big difference to my behavior. There are all kinds of things I do for purely economic reasons that I could stop doing and concentrate more on the things I care about for their own sake. But to figure out how to act, I need to know: did he leave me the money or not?
The same may well go for the man asking Mr. K the question. Even if Mr. K is right in guessing that the questioner "needs" to believe in God for whatever psychological reason, the question of whether there really is a God still seems to be the real issue. The questioner's "needs" might change depending on the most plausible answer. (And by the way: it could be that the questioner fervently hopes that there isn't a God but is anxious out of fear that there might be.