The bastard had ruined MC family by chance, he mostly wanted steal away things from MC, the stepsister having a yandere core was a miscalculation, or being brainwashed so young broke her brain, is pretty sad because it utterly broke 2 families, given her outbursts towards MC mad ethe family unabel to stay together so the parents had to leave.
MC mother is a big catch and everyone that knows her lvoes her, she was like that from a young age, most likely for the chaos it produced it made someone cast a spell on people to not be interested in her or something similar as the bastard rapist only thought of stealing her away when pushing his brain to the limit on what he could take from MC, he was surprised of never thinking of the mother, and not remembering how she looked, but right in the minute he started planning that out MC punched him out.
After the charm was dispelled the stepsister tried to get back with MC istantly, as her feeligns returned, but she didn't want to accept or recognize the selfish acts she made under it, so MC refused her harshly, little girl even ruined her relationship with her father in a terrible way, lost all his trust, that is why I hate the bastard, he ruined other people life for fun, a psychopath, and the town have a ton of cases like that, MC was his main target but he did the same to many others, the most stupid part is no one tried to kill him.
MC should not be a wimp, he is a bit in the manga, but in the novel he doesn't care or apologize to people without reason, the angel in the previous chapter got a severe beatdown, the classmate family got treated like inferiors when here he looks dumb.
Is not caring about the rapist is because he genuinely doesn't care about others, 10 years in hell made him selfish.
He helped the alien out of curiosity, healed the clasmate he killed because he didn't want troubles later, he agrees to the mother request because he get compensated for the trouble.