Good grief the human men are stupid as can be as well as being assholes. Instead of escaping with the women before the orcs get there they waste their time raping the women. Heck the women would have probably begged the men for sex if they had rescued them." Oh look I raped these women but I was killed for my stupidity."
While it's a very hot story, it would be hugely problematic not just from the phycological problems of a granddaughter and her grandpa having sex but there could be really bad genetic problems if she gets pregnant. But it's nothing more than the writer's fantasy.