i am reading this again, I find the Dad although not very bright, a very strong man.
He lost his memories when he was young. His savior died when he was 15. He has been living by himself until he married. But then his wife got so weak than she cannot leave bed. One of his son also got weaken...
The girl is a different girl now. She is not the same girl the MC liked in the past. But well, the MC is a different person now as well. You can say that they both died years ago and then reborn as forking badass killers
@UnknownSaint111 fun fact. with 50 couples, we can recreate a healthy (non-inbred) population. If there are more than 100 adults in the tribe. It's safe to assume there is no incest.