Yeah, but he didn't know what she didn't know, so how was he supposed to know how to help her know it without awkwardly stumbling over things she did know???

Prompto looked warily back at Liliana, took in a deep breath, and decided to just info dump everything he could possibly scrounge up about turning, tip to tail, anatomy of the car and offers to slip under the carriage to show her, even, with an extra emphasis whenever he referenced the pivot point, acceleration points, blah di blah blah blah and leave it up to her to decide what was useful.

Which, like, he knew she had a phone,did that phone just not have google?