Well since it’s all in the family, why not skip the pretending and just have the old guy jump into bed with his daughter in law and get it over with?
Rather than pretend it’s somehow less disturbing to use a syringe.
It seems like adultery to me too. Granted her husband has consented and it’s a different method, but she’s still having his sperm inserted inside of her. Whether he does it through a test tube or the natural way, the same end is occuring. Either way she’s having the child of her husband’s father.