A: You may consider your non-Muslim father as your Mahram, thus uncover (parts of the body that can be exposed in front Mahrams) in front of him.
Imam al-Kasani (Allah have mercy on him) states:
“A Mahram is one with whom marriage is permanently unlawful… whether this Mahram is a free person or a slave, for slavery is not contrary to close relationship (mahramiyya), and whether he is a Muslim, a non-Muslim or an atheist (mushrik), for a non-Muslim Mahram normally safeguards her, except that he is a fire worshipper, for he considers marriage with her to be permissible.” (Bada’i al-Sana’i, 2/124)
However, if there is a fear of temptation (fitna) on either side or you fear that by kissing him, he will have evil thoughts and desires, you must avoid uncovering in front of him and kissing him. The jurists (fuqaha) have stated that, covering becomes necessary even in front of Mahrams if there is a fear of Fitna or desire.
Today we live in a time where sexual impropriety is becoming common in non-Muslims, thus one must be careful. If your non-Muslim father is old or you feel that he will have no evil thoughts, then it would be permitted to remove your Hijab in front of him and kiss him.
And Allah knows best