He was fucked in the head from the start, but he got worse over time. He was in special education school for behavior issues (not autism!) as a kid, got in trouble with the law, was tested for a bunch of crap and was found to be stupid (IQ in the 80s), but not mentally retarded. There’s also other legitimate health issues he may’ve had with an undescended testicle, and legitimate mental health issues since he was apparently molested.
However, even when he was “functioning” like working at McDonald’s or running his blog he was engaging in his diaper fetish and generally being a dumb asshole. Whether the hit and run actually happened or not, it took years of abusing his family before he became what he is today. TBIs can change personalities and make people angrier and needier—I have a relative who was an asshole after having a stroke, as an example. But this developed over years and IMO probably didn’t come from brain damage. This is a grown man, stupid and considerably mentally ill, pretending to be helpless and developmentally disabled to get other people to engage in his fetishes and let him spend all day on the internet. It’s his own fault not his family, but you’d think years ago they would’ve realized that locking him in a padded cell for life or putting a 9mm through his skull were the only options.