Frizl. Havn't seen this brought up by anyone, any thoughts?

How is it that such a monster, who acted with such cruelty and premeditation, A. let the 19yr old girl go to get hospital treatment, and B. let his daughter go and gave himself in? It amazes me that he didn't just kill the 19 yr old girl... He has a previous conviction for a violent crime, and has previously disposed of a body... or at least just let her die like he did the twin years ago... Does this monster have some kind of feelings after all? It can't possibly have been fear... Is there some phsychological block that stops a man from murdering his daughter/granddaughter - even such a man who imprisons and s his own daughter? Or isit just that he got old and decided what the heck, he has nothing to live for anyways why not let them go? What's going on? What changed phsychologically in this person?