Is it permissible to attend the funeral of a non-Muslim friend who was kind?

A Muslim is not permitted to attend the funeral of his atheist friend. Sheikh al-Islam Ibn Taymiyyah was asked if it is permissible for a Muslim to follow the funeral of a Christian when he dies, and he replied: "He should not follow his funeral." Khalil said: "A Muslim should not wash a disbelieving father, nor place him in his grave, unless he is left to perish, then he may bury him." Befriending evil people is a great danger due to the possibility of one friend imitating the other. The Messenger of Allah, peace and blessings be upon him, said: "A person is upon the religion of his intimate friend, so let one of you look at whom he befriends," and he said: "A person will be with whom he loves." Therefore, a Muslim should befriend the pious and avoid evil people.