Sorry to read that. Two things however, from a JW point of view, talking about the Bible doen't make someone outside the Borg righteous/valid in his/her argument... didn't satan quote the OT against Jesus?
Second, Lot wasn't under the Mosaic Law and getting drunk and having sex with his two daughters may have been a case of "the mind is willing but the flesh is weak" in Jehovah's eyes. I know, I know... just saying... ask king David how that stuff works...
As long as JW's consider the GB to be GoD (Guardians of Doctrine) everyone else can be considered wrong regarding their own interpretation. Your father needs to see through the indoctrination first...I hope that will happen one day.