From what I recall from back in the day, there wasn't like a video interview or anything.
Long back story time: Phil's Internet or something went out one day because Kat unplugged the router to vacuum. Phil was unable to stream vidya so he had a Q&A stream. In this stream he mentioned he had a new car. The detractor community picked up on this because as far as we knew he only had the shitty used Corolla. The detractors used their autism to search up insurance records for Phil and Kat to see if there was a new car. There was no new car but they discovered that Kat was also insured on a Subaru in Michigan along with her ex, Jeff. This is how he got the name "Subaru Man".
Detractors descended upon Jeff's socials. He was obviously annoyed at dozens of strangers messaging him because his ex was now dating Phil. He made a statement somewhere giving us all the known lore such as Kat not knowing how to cook, her general laziness, how he found out she was messaging the "Streamer Guy" behind his back, etc. etc.
Tevin took this info and made a video explaining it all. He also found Jeff's YouTube and the infamous "Hair Tricks" videos.
As far as I know he never directly was in contact with Jeff or interviewed him. But I could be wrong and just never saw it. I was a pretty regular watcher of Tevin at that time so I'm pretty confident in my memory.