Is it permissible to treat a foreign man like a father in the workplace, especially if he kissed the employee's hand and she reciprocated the kiss, considering him to be in the position of her father, and is this action forgivable for her?

Respect for elders is a religious requirement, but a woman's interaction with a non-mahram (definition) man has regulations. It is not permissible to allow him to be alone with her or to shake his hand. Kissing the hand is even more dangerous. The duty is to repent and beware of following the footsteps of Satan, for Satan commands indecency and evil. And a woman's work in a mixed environment has legitimate Islamic regulations.