We know that if my brother is Kuffar than I don't have to keep kinship with him. But what about if he is Munaafiq (hypocrisy)?

All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.

Hypocrisy is of two types: major hypocrisy that takes a person out of the fold of Islam, and minor hypocrisy that does not take a person out of the fold of Islam.

The major hypocrisy that takes a person out of the fold of Islam is related to the faith, such as concealing disbelief and claiming belief or that a person commits an act that takes him out of the fold of Islam, such as mocking the religion of Islam or the Prophet (may Allah exalt his mention). Such a person is a disbeliever and keeping kinship ties with him is not compulsory if he is among the blood-relatives.

The Fiqh encyclopedia reads: “There is no disagreement that a Muslim child has to keep ties of kinship with his non-Muslim parents. But keeping kinship ties with other non-Muslim relatives is not compulsory as Allah Says (what means): {You will not find a people who believe in Allah and the Last Day having affection for those who oppose Allah and His Messenger, even if they were their fathers or their sons or their brothers or their kindred.} [Quran 58:22] This is the opinion of the Hanafi, Maaliki, Shaafi'i, and Hanbabi Schools of jurisprudence.

Furthermore, Imaam As-Samarqandi reported that Sahnoon ibn Mohammadaan said: “Muslim and non-Muslim relatives are equal as far as the matter of the ties of kinship is concerned.”

According to the view of the majority of scholars keeping ties with a non-Muslim is not religiously required except parents. However, severing ties with him is allowed when one loses hope in guiding him. Ibn Hajar said: “Keeping ties of kinship with non-Muslim relatives should be only if one feels that they will repent from disbelief or at least hope that their offspring will embrace Islam. A Muslim who keeps kinship ties with a non-Muslim should have such an intention.”

As regards minor hypocrisy, it does not take a person out of the fold of Islam; the evidence is the saying of the Prophet “The signs of a hypocrite are three: whenever he speaks, he lies, whenever he promises, he breaks his promise, and if he is entrusted, he deceives.” [Al-Bukhari and Muslim]

These are dispraised characteristics and whoever is characterized by them has a kind of hypocrisy but he is still a Muslim and is not out of the fold of Islam. If such a person is a relative, then he has the rights of kinship and severing ties with him is not allowed unless there is a religious benefit in deserting him, such as him giving up his sins.

Finally, we inform you that declaring a Muslim as being a hypocrite is very dangerous. It becomes more dangerous if he is accused of major hypocrisy since it is accusing him of disbelief. The Prophet said: “Any person who says to his fellow Muslim: ‘O, Kaafir’, (disbeliever), then one of them (the two people) draws that on himself. If it is true, it is as he said, otherwise it is returned to the one who said it.” [Al-Bukhari and Muslim]

We also advise you to keep kinship ties with your brother if you hope that this may result in his guidance, and you should strive to advise him and call him to embrace Islam, as Allah may guide him to the truth.

Allah knows best.