Yeah that's a good point, why would the mother get married and hook her daughter up with a much older man if they only needed her to get pregnant? Maybe the MC looks a lot like the dead father?The daughter got 50% of the dead man's DNA. By making a child you can get him back 25%. Why you need an older man like our MC for that idk. Crazy people plans don't need to make sense.
This is when I remember the title of the story:
"Welcome Back, Papa"