@Edjan To your points:
1. No, it's not wrong. That's just your morale you got from society. The higher risk of deformations and mental issues isnt fully proven and even people who have the issues to begin with are allowed to have children which gives them a higher risk of getting them too. It's just the public ego that disavowes it.
2. Doubt he will have any luck changing the attitude of a yandere.
3. That right, he's just an egoistic fuck that only cares for his own needs. His family will probably feel the consequences for his leave.
4. Who knows, he had help with it anyway.
Conclusion:
1. You're right.
2. This chapter has proven to me that the autor is not good at creating a story.