My position on WillCare
My take was that William was never really a good person. He was a narcissist, had latent sociopathic tendencies, and was a cutthroat ruthless businessman. However, he was someone who had largely learned to suppress his worst side, who was a loving-if-distant presence in his children's lives. I tend to think BV (Evan, Dave, whatever you want to call him) was the favorite, with William having a far less close relationship with Mike, possibly because Mike reminded him of his own worse traits. This led Mike to lash out at his sibling, bullying him, which William, an older man, approached with a very "boys will be boys" attitude, and, as William got more and more involved in the business, he grew more and more distant from his family, which left Mike often with babysitting duty. This led to the bullying getting worse, cultimating in ya know what, which led Afton to become outright physically abusive to Mike as a way of taking out his anger, and then Afton giving in to rage and resentment and grief to drunkenly murder Charlotte in a back alley. And that awoke the darker side of him that he'd tried to keep underwraps. You never know what hobbies you might enjoy, when you give them a shot...Once he learned of Remnant, he latched onto the idea of bringing back his son as a way to justify his killings, but, in truth, he had come to enjoy it and that was just a thin figleaf to pretend he wasn't a monster.
TLDR: William Afton was a narcissist-with-sociopathic-tendencies, a neglectful-but-likely-not-outright-abusive-father, and a ruthless businessman, but did love at least one of his children, only to go skiing down the slippery slope after the Bite. I don't think this in any way justifies his actions, if anything, it makes it a bit worse, in my mind, if Afton was once someone with the potential to be a decent or at least FUNCTIONAL member of society, but chose to give in to his worst impulses and become a murderous abusive scumbag. He didn't have to be this way.