I suspect ESTJ. I have the same experience with my boyfriend, that it takes more explanation to get him to understand my meaning and intentions when I am discussing things in the abstract. Though it could also be the nature of dominant T in tending to grasp logical concepts first and holistic concepts later.
I think it’s probably this. From the OP he sounds more ENTJ to me. From my experience INTJs often “get†things more quickly than ENTJs, although ENTJs aren’t slouches. The fact that he’s trying to “get†it at all is another reason to lean ENTJ in probability. There are ESTJs who will attempt to stick with an abstract discussion, but they are much fewer and farther between.