as others had said, it is impossible to change an old man's mind. but our mind can change to adapt the situation.
do u know this story:
it is very difficult to cover the whole surface of the earth to protect our feet from being cut by sticks and stones. but by covering only the surface of our feet with leather it is as if the whole surface of the earth were covered with leather.
i think these words are very enlightening.
we know the situation and we know we cannot change it. so why not accept it and protect ourself well? anyway, he is her dad. she must take care of him.
therfore, the best way i think is protecting herself well. let her dad be himself and let her be herself.