Well, then don't try and ascribe him to the INFJ description, personality types were never meant to match up to a single description in the first place. That is the fallacy of MBTI. All that matters is what cognitive functions he is using, if he is an Ni dominant, and using Fe auxiliary, then how he is using these functions is completely irrelevant.
I'm sure you have theoretical philosophies concerning society as well. That is a result of our Si worldview being connected to our Fe. Which actually makes it a rather similar worldview to the INFJs because their Ni is connected to their Fe. Here is the difference: We are not going to act on it like they are. For an INFJ turning their Ni vision of how society should be into reality is their heroic drive. As INFJ they are driven to actually make the world more like their Ni vision is telling them it should be. ENTPs, as well as us, do not have this visionary drive that the INFJs have. The ENTPs live in the world of infinite possibilities, but Ne possibilities are not directive, in fact they are the opposite of Si, so narrowing things down to a single truth is exactly what Ne is not about.
Ah, okay there is something important I need to point out: there is a difference between being articulate and being an extrovert.
Despite popular belief, being an extrovert has nothing to do with how much you talk. Being an extrovert simply means your dominant function is an extroverted one. However your ability to articulate actually comes from how well developed your Fe or Te is, depending on which of them you use. Naturally an Introvert will lose more energy from articulating just because it is unstimulating for them to engage with the external world, but that does not necessarily mean they are going to be silent, and socially incompetent. In the same way having a dominant extroverted function does not mean you are going to be super talkative either (ENFPs for instance are very often quiet people.) The act of extroversion is simply engaging with the external world, this could be in the form of listening to a person speak, being aware of your senses, being aware of the present patterns, or even drawing a picture.
INFJs in particular are very often confused for extroverts because of this misconception, and because Fe is their secondary function. So when an INFJ has a well developed Fe, then they can become very articulate, and connectible with other people.