There is only one way for him to tell for sure.

I've said elsewhere i'm really fascinated by the existence of Katty in the contest of the series, as made me think and wonder what story there behind them and their mother. Is intriguing(it does not help that their mother, with all the funny charme made me think, god know why, to Dolores Claiborne(the fact that Kitty and Katty dad is nowhere to be seen does not helo me get rid of this odd overlappin in my fantasies...)