بسم اللہ الرحمن الرحیم

:الجواب ومنہ الصواب

It is not allowed to maintain relationship with an apostate, because he or she is a disbeliever. In the Holy Qur'an there is a clear command to cut ties with those people. 

Almighty Allah says:

"ومن یرتدد منکم عن دینہ فیمت وھوکافر "سورۃ البقرۃ

لایتخذ المؤمنین الکافرین اولیاء من دون المؤمنین  (سورۃ آل عمران)

Therefore, your attitude towards them is correct. It is right for you to stay away from them, and your parents should also cut ties with both. Also, do not involve them in your ceremonial gatherings or in other family matters. Do not share your joys or sorrows with them, so that the ugliness and abhorrence of blasphemy and apostasy remains in the hearts of Muslims, as well, a warning to the apostates and atheists. It is highly important to demonstrate that the love of Allah (SWT) does prevail over the affection of worldly relationships, otherwise, they would become sinners. 

Nevertheless, if there is hope for reforming the apostate and to bring him or her into the fold of Islam, then there is room for maintaining that relationship. In that situation, it is important to guide and encourage the apostate towards Islam in the best manner possible and to keep praying for their return to the blessed faith. As for entering the Masjid, the infidels and apostates are allowed, provided they are bodily clean and from any ritual impurity. 

(مستفاد از امداد الاحکام جلد4 صفحہ :393)

فقط واللہ اعلم بالصواب

کتبہ: مفتی محمد رئیس منھاج