Is it permissible for a father to prevent his daughters from studying in mixed-gender schools, while allowing his sons to study in them, knowing that studying in the mosque is of lesser quality?

Mixing of genders in schools is forbidden due to the danger it poses to chastity and morals. The guardian must prevent the adolescent from looking at forbidden things. It is not permissible to study in mixed-gender schools, even if the student finds no other option. Studying in mosques is preferable, even if they are of lesser quality, to protect one's religion and honor.