Not saying he isn't guilty of being greedy or something, but often-times victims of sexual abuse don't realize what they experienced was actually sexual abuse because they either rationalize it as normal behavior or think they brought it upon themselves somehow.
Again, I'm not saying I know the facts, but I do think it's conceivable for him to go from saying MJ never sexually-abusing him to finally admitting it after intensive therapy sessions and learning more about the nature of sexual abuse.
Mackenzie Phillips wrote in her biography that her father and her engaged in incest, but that it was consensual. She changed her mind about the last part when she spoke to other victims of sexual abuse and realized that she did not really consent to the sexual advances or that the power a parent or an adult figure has on a minor makes it so that a victim really thinks it's consensual when the victim could not have fully consented psychologically.
Anyway, it's not as if he's a nobody. He's been working steadily for the past few years in some high-profile projects. That doesn't mean he doesn't have money trouble or that he doesn't see big dollar signs because whatever money he is making (which I assume is a lot), it's nothing compared to what he can win if his suit is successful. That said, he's putting himself through incredibly scrutiny and skepticism if he's only doing it for the money.