If you read those texts closely, there had definitely been something going on between BH and Read. They were flirting heavily in the texts, basically using texts after an impulsive kiss one night, to feel each other out in that awkward way where you are interested but don't want to be too transparent about your feelings. Both were interested. Neither said no. Both wanted more. Each wanted the other to be more openly aggressive. Both knew "I have flaws" and as experienced adults were clearly being wary as a result. Lot's of expressions of being free to do as they pleased. Many comments about drinking, but it sounded more like their social construct ("join me for a drink" and "do you have anything there to drink" and "are you going out for a drink") to enable uncommitted -but-exploring interaction than a desperate desire to consume alcohol.
It stands to reason they moved from texting to communicating by phone calls, and then talking (and more) in person. Reading between the lines (where there are gaps in texting), there had definitely been some sort of relationship that included meeting up at her house, his, or both. But did they continue to chase each other, or did things between them flame out quickly? Not enough here to answer that.
All that having been said, it doesn't really explain how JOK died, since he wasn't hit by her vehicle. But it does make me want to know way more about Higgins' actions that night.