What's a good way to distinguish between someone's use of Ti versus Te, if the person's evenly balanced in their usage of Fi/Fe due family arguments/dynamics forcing them to consider both perspectives? I'm trying to type a close relative who's either an ESFP (Fi/Te) or ESTP (Ti/Fe) here. Any further advice on typing them would be appreciated.
People who use any thinking functions as their dominant or auxiliary are searching for logic, but their methods and reason for doing so will be different.
I get upset when there's a lack of logic, because it's inefficient. It wastes my time. I like to have an external system in place to expedite the processes by which I do things. That's my logic, that's my Te.
My coworker is an INTP. He always wants to know why. He can't deal with the world around him if he doesn't know the logistics of it. He wants internal systems to understand the world through analysis. That's his logic, that's his Ti.
What you'll want to look for is a dominance of logic leaning more towards my coworker's. If that's present, in addition to a tendency towards charisma and being at least somewhat able to read the people around them, it's probably Ti/Fe.
If not, and they tend to move around on a basic moral structure, but also tend to put the world around them in a logical order so that they can move through their world with greater ease, it's probably Fi/Te.