Of-course as far as story goes, MC is not blameless at all. But there are pretty thick cushion points for the man.
One. As someone already stated, MC as a kid decided to distance himself from his sister to prevent being bullied was a plus move. And I believe it was a couple days, a week at most. Then their parent intervened, correct?
Two. MC standing up to the rapist-friend. It was a foolhardy thing, but I believe Jay herself admitted afterwards that "it was exactly what she needed from MC". Word-for-word.
Three. He "left" his family. MC was an eighteen-years-old kid with a constantly antagonistic family member. He was also someone who had a big trust-fund who later got an itch to travel the world. It's pretty douche-y the way he did, but it was his choice to do whatever he wanted with his legally-adult life.
Overall, Jaye was left with pretty significant drawbacks as a love-interest. The worst (for me at-least) was when they reunited, the first thing she did to the MC was interrogating why he wasn't at the funeral, and why he didn't contact her. All in-front of the will-overseeing third-party family friend, and her own significant other. She didn't ask how he was all these years, how he was doing about their parent death. No. It's pretty much all about her. That's a big yike if I ever saw one.
I am invested in characters because this game got a fluid story, and interesting mystery behind it. But as far as love-interests go, Mallory's more than a head and shoulders above Jaye.
Sorry, if I got anything wrong. English isn't my first language.