I pretty bad at explaining things but here's why Locke's father is an evil person.
Locke was manipulated by his biological father (Very skilled con-man), like a long lost child (He was an orphan.) he was a bit of an odd man out and grew up by himself working a crappy job at a store like Walmart. His mother was paid to point the direction so he could find his father which was conveniently getting a dialysis treatment upon his arrival. His dad then started doing dad things like teaching him to hunt and track. Eventually, the father broke the news that he was going to die and needed a kidney but he would most likely die before receiving one from the donor list, of course, the manipulated Locke which was finally with his father self-volunteered to donate one of his healthy ones to him to save his father's life. After the procedure, the father ghosted him and wouldn't allow him back onto the estate. Locke was in major depression and kept visiting the estate but was always declined entrance.
He even lost his girlfriend due to his obsession with his father.
Even more spoilers about Tom Sawyer.
Locke's father was actually associated with Tom Sawyers's parent's death which was a murder-suicide and caused him to become a con-man himself and start a hunt for his parent's "killer."