why did the mother and daughter get naked and lay in bed with him ?
Body heat to keep the man warm so he would recover from the fever.
To elevate his body temperature. My guess is that he was battling an infection. When someone is hypothermic, another person's body heat can raise their temperature.
that was my thinking.. but why did they have to get naked? why not just put more clothes/blankets on him and then lay next to him for body heat?
skin to skin is the most efficient way to transfere heat... women have a slightly higher body temp than men