Boys should be taught that women aren't sexual objects, yes, but the daughter should also be taught that there's a time and place for everything and not everybody will be comfortable with somebody's nudity, nor is it, in many places and situations, socially acceptable to be in the nude. One person's comfort level (being nude) shouldn't trump another person's comfort level (not knowing where to look when a nude person's all in their face). Perhaps she can be in her room nude, but cover up out of respect for certain family members feelings when she comes out of her room? And what about company, or if you need to call a repairman to the house, or if the younger brothers want to invite friends over? Not only could that be uncomfortable, or even dangerous, but some people might even press charges if a teenage girl is walking around "showing" her body parts to young boys.Boys should be taught that women aren't sexual objects. That's like saying "you have boys at home so dont breast feed because breasts are well... boobs."
I do agree, that it somewhat weird for her Dad to be all for his teenage daughter walking around naked. I'd be very careful on that one, for CPS reasons.