Impurity for a Kohen with a Dying Relative

A Kohen whose father is dying, is he allowed to stay with him at the moment of passing, or must he leave?

According to Halacha, a Kohen is prohibited from being in a room with a dying person. However, regarding his father, since he is commanded to become impure for his father, according to the Shulchan Aruch, which permits impurity even without necessity, he does not need to leave, and even according to the Rema, it seems permissible to be lenient.

It is stated in Nazir 43a: "The Rabbis taught: 'until he dies'. Rabbi says: 'in their death, he shall become impure until they die'. Rabbi Yochanan says: 'the difference is in interpretation'. Resh Lakish says: 'the difference is in the dying person: according to the one who says 'until he dies', even a dying person, and according to the one who says 'in their death', only after death, not a dying person'. The opinion of the Ran and Mordechai is that the law permits a Kohen to become impure for a dying person. However, the Baal HaGaon wrote that the law prohibits becoming impure for a dying person.

The Shulchan Aruch, Yoreh De'ah, Siman 373, wrote that a Kohen is prohibited from entering a house with a dying person by law. However, the Rema wrote that one should be stringent not to become impure, implying that by law he may become impure. In the Shach, Siman 349, it is stated in the name of the Bach that he agrees with the opinion of the Ran by law.

Regarding his father, whom he is commanded to become impure for, the Shulchan Aruch, Yoreh De'ah, Siman 373, Paragraph 5, ruled: "All those for whom he must become impure, even without necessity. And some say only with necessity." Thus, he ruled that it is permissible to become impure even without necessity. However, the Rema there wrote: "And it is proper to be stringent as the latter opinion, to become impure only for burial and to bring him a coffin and shrouds." In the Shach, in the commentary, it is written that the main opinion is like the first opinion. In Aruch.

Thus, it seems that since the Rema ruled that by the main law a Kohen is permitted to become impure for a dying person, and he is stringent to consider the opinion of the Baal HaGaon who prohibits, and also holds that he may become impure even without necessity but is stringent to become impure only for necessity, it can be said that he was not stringent in both cases to prohibit becoming impure for a dying person and for his father without necessity. Moreover, it is possible to add here the opinion of the Minchat Chinuch that even those who are stringent not to become impure without necessity agree that anything done for his honor is permitted, and they only prohibited becoming impure to check whether he is male or female, and although the Rema certainly disagrees, nevertheless, with the above opinion, it is possible to be lenient.