My Ni perspective-shifting moves drive my INFP crazy. I mean, seriously, she feels it's evasive and changing the topic etc etc when I do that perspective shift thing in response to something she asserts. So for example, this past weekend, she made a statement and asked me if I could give her an argument showing that what she said wasn't true. My first/immediate response was to move outside the parameters of what she laid out and look at her statement from a different perspective entirely. She didn't like that at all. She said I was trying to change the topic and was being evasive. I said that her statement was so limited in its parameters that it left no room for anything outside of itself. For me, it's like my first instinct in situations like that is to note and then move outside the set parameters and look at the topic from some other perspective(s). And again, she finds that maddening and from that space of finding it maddening, judges it pretty harshly as a problematic way to move, a process she feels is almost designed to confuse others and blur things up.
I'm slowly learning that the only way I can usefully interact with her in these circumstances is to accept her parameters for the purpose of the interaction, and try to simply understand what she's saying inside of those parameters, while staying clear in myself that she won't move outside of them so in myself I have to understand the discussion as severely limited because it doesn't allow for the kind of perspective shifting that I instinctively want to do. This is probably Ni+Fe at the very least and I don't know what Ni+Te would do with such a situation.
Thing is, I don't necessarily see a parallel between the INFP/INFJ dynamic I described and how you describe your experience with your friend. And too, I don't know if or how such a dynamic might translate to INTP and INTJ - especially since T orientation is switched and in different locations and that renders the comparison conceptually confusing to me to the point of near meaninglessness.
However. I still feel it worth it to post this just in case. So I will say this: if by chance there is in fact some kind of parallel here and there is some sort of INxP/INxJ confusion thing happening here (specifically if anything he's doing is due to Ni perspective shifting that is coming up against something in you that isn't ok with those kinds of moves), your experience and description of your friend's actions cannot be taken as straight-up description by any stretch of the imagination. Instead, it will be a description based on your specific take on and location in the experience in a particular dynamic, and it will cast an understandably negative light on what your friend is doing. It's like how my INFP would describe what I do as changing the topic and evasive .... while I would describe what she does as limiting the topic to the point of creating truisms for herself.