Ruling on mocking a sinful Muslim
20-5-2013 | IslamWeb
Question:
Assalaamu alaikum, Not sure this is the right section.There is a Muslim who believes but quit praying and has been involved in many major sins. Another Muslim got upset with them as they do not heed advice and calling them back to Islam and mocked them. Is the repentance for this sin to Allah swt only or to that person as well? Ok, I explain more. There is a brother, who prayed for many years, fasted, gave charity, supported orphans. Then due to ongoing troubles with spouse instead of getting divorce he started to quit islam, as the marital problems became so huge he wanted to pay the spouse back by doing evil things as well. In the end he stopped praying, eat pork at times, have a glass of wine here and there... The brother has a best friend who was for a long time kept in the dark and knew nothing about these problems. One day it came to light and the friend has been trying for some time to call him back to islam, show him the way out of the situation, tell him that haram only leads to bad things etc, all to no avail. So one day the friend quit the frienshinp in anger and mocked him saying YOU MUSLIM HA HA. I need to add that the brother doesnt deny Onness of Allah.
Answer:
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, sallallaahu ‘alayhi wa sallam, is His Slave and Messenger.
First of all, whoever commits prohibited mocking, his repentance should be through regretting it and resolving not to go back to it. It is not a condition for his repentance to seek forgiveness from the one whom he mocked according to the preponderant opinion we adopt here in Islamweb. That is because if the right can be restored such as money or the like, it should be returned to its owner. However, if it cannot be restored like in the case of gossip, talebearing, mockery and the like, then supplicating Allaah The Almighty in favor of the person whom one harmed, seeking forgiveness for him and mentioning him with good words will be sufficient. That opinion was adopted by Shaykh Al-Islam Ibn Taymiyyah 
who stated that it is the opinion of most scholars and also adopted by Ibn Al-Qayyim . The prominent scholar As-Saffaareeni stated that it is the opinion of the majority of Muslim scholars.
However, what that man who advises the sinner said by asking him: “You Muslim Ha Ha?” does not seem to be prohibited mockery; rather, it is astonishment of his claim to be a Muslim while insisting, after advising him, on abandoning prayer, drinking wine - the mother of all evils - and eating pork. This is really a matter that makes one astonished. No doubt, faith encourages one to avoid prohibitions and fulfill obligations, especially prayer which is the main pillar of religion.
Confessing the oneness of Allaah The Almighty is not sufficient in itself to deem someone Muslim. Many non-Muslims such as Jews and others confess that Allaah is one while they are unanimously disbelievers.
Moreover, many jurists view that one who neglects prayer is guilty of major disbelief which takes him out of the fold of Islam for the Prophet, sallallaahu ‘alayhi wa sallam, said: “The covenant that distinguishes between us and them (disbelievers) is the prayer, so whoever neglects it has disbelieved.”, although that person may be one who confesses that Allaah is One.
Hence, if we suppose that he is a disbeliever and that the word that the advisor said is mockery, then the Quran indicates that it is permissible to mock the disbeliever. Allaah The Almighty says (what means) about Prophet Nooh (Noah) 
that he said to the disbelievers among his people: {"If you ridicule us, then we will ridicule you just as you ridicule.} [Quran 11:38]
Also, Allaah The Almighty has told us that He The Exalted ridiculed the hypocrite who defamed the believers who gave charity voluntarily and ridiculed them, and He mocks the disbelievers who are mockers for they deserve mocking and ridiculing.
Thus, we do not see any harm regarding what that advisor said. Rather, we should search and ask about how that sinful person who neglects prayer, drinks alcohol and eats pork can repent from that is more appropriate and important than searching and asking about how an advisor can repent from having said a word that may not be prohibited.
Finally, we draw attention to these two important matters:
Firstly, beware of hastening to judge a Muslim individual as a disbeliever just because he committed a sin or an act that puts him beyond the pale of Islam. That is because whoever enters Islam with certainty cannot go out of it except with certainty. Also, there is a difference between deeming an action a form of disbelief and deeming its doer a disbeliever, for not everyone who does an act of disbelief is deemed disbeliever because he may have done that due to misunderstanding or ignorance. Whoever falls into disbelief is not deemed disbeliever except after establishing evidence against him. So, scholars said: Not everyone (among Muslims) who falls into disbelief becomes a disbeliever. For more benefit, please refer to Fatwa 91677.
Secondly, one should strive to call that man kindly, leniently and wisely so that he may repent, return to Allaah and give up what Allaah The Almighty has prohibited. The Muslim individual, in spite of what may occur from him, has a seed of goodness in his heart that needs to be cleaned from the dust of sins so that it may grow and increase. Therefore, his friends should strive hard to call him to Allaah.
Kindly, refer to Fataawa 13288 and 16419 about the etiquette of enjoining what is good and forbidding what is evil, and Fatwa 86527 about the conditions of sincere repentance.
Allaah Knows best.