The two angels who are appointed to write the good and bad deeds of a person never depart from a Muslim in writing his good and bad deeds unless he is in a state of impurity, in which case they stay away from him until he purifies himself. What about the non-Muslims who are always impure, who writes their good and bad deeds if the two honourable appointed angels stay only with a pure person?

All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger. We ask Allaah to exalt his mention as well as that of his family and all his companions.

The two honourable angels appointed over each individual person do not leave him for a second at all and do not stay away from him in any case, whether he is a Muslim or a non-Muslim, pure or impure. As regards the angels who depart from a person, they are the angels of mercy. 'Ammaar Ibn Yaasir narrated that the Prophet said: "There are three kinds of people whom the angels do not approach, the dead body of a non-Muslim, a person who abundantly applied coloured (reddish or yellowish) perfume and a person who is in a state of sexual impurity." [Abu Daawood] The author of 'Awn Al-Ma'bood said: 'The phrase ‘the angels do not approach them’ refers to the angels who descend with mercy and blessing on mankind, and it does not refer to the two honourable angels appointed over each individual person as they do not leave a pubescent person in any case.' 

Allaah Knows best.