Is it permissible for a woman to uncover her hair for treatment by a male doctor if a female doctor is unavailable, knowing that her father forbids it on the grounds that hair is 'awrah?

It is permissible for a woman to seek medical treatment from a male doctor when there is a necessity or need. If a female doctor is not available, it is permissible for him to examine her to the extent of the need, provided there is a mahram present, and that everything but the area of illness is covered.