Relations with an aunt who refuses to pray and says she has no sins
1-2-2000 | IslamWeb
Question:
I have an aunt who lived in America for more than 20 years, who refuses to learn how to pray. Am I allowed to love her and show her my concern? I tried to tell her that God may forgive all sins. She answered that she has no sins. Should I ignore her, or try once more to talk to her gently?
Answer:
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.
The Prayer is the first act of worship which Allah has ordained and it is the most important pillar of Islam after the two testimonies of faith, which is to say: “Ash-Hadu Alla Ilaha Illallah Wa Ash-Hadu Anna Muhammadun Rasoolullah” (I testify that none has the right to be worshipped but Allaah and I testify that Muhammad is the Messenger of Allah).
It is for this reason that Allah took the responsibility of directly imposing it by personally addressing His Prophet on the night of Al-Mi'raj (The Prophet's ascension to the seven Heavens).
The prayer was also the Prophet's last advice to his nation before breathing his last as he said: “The Prayer, the prayer and whatever your right hand possesses”. [Abu Daawood and Ibn Maajah]
Also, the prayer is the first act for which a person will be held accountable for and it is the last thing that will be lost from the religion of Islam. Allah Says (what means): {But there came after them successors [i.e. later generations] who neglected prayer and pursued desires; so they are going to meet evil.} [Quran 19:59] Ibn Mas'oud 
and others, said (while interpreting the verse): “Neglecting the prayer means delaying it from its prescribed fixed time and if they abandon it, they would be considered as non-Muslims”. Besides, the Prophet said: “The head of the matter is Islam, its pillar is the prayer, and the top of its hump is Jihad in the way of Allah”. [At-Tirmithi]
Indeed,‘Umar wrote to his workers: “The most important matter of yours in my sight is the prayer, so whoever guards it and observes it regularly, he thereby preserves his religion, and whoever neglects it, he would be more neglectful towards other matters of his.”
Hence, is there any greater sin for your aunt than abandoning the prayer and being neglectful about Allah’s Obligations and claiming that she has no sins? She is too self-confident and claims falsehood while she continues to abandon the greatest obligation in Islam.
According to the view of the majority of the scholars, a person who deliberately gives up the prayer is to be killed after ordering him/her to do his/her prayers thrice. Then they differed in opinion whether he/she should be killed because of apostasy or just as a way of implementing the Hadd (i.e. the corporal punishment determined by the Islamic Law).
Your aunt should know that by being persistent in abandoning the prayer, she commits a grave major sin that is even graver than committing adultery, consuming intoxicants and killing a soul which Allah has forbidden to kill except by right.
Therefore, you should advise her and warn her against the Anger and Punishment of Allah. If she takes heed, this is what is required, otherwise you should not establish relationship with someone who fought against Allah by abandoning His Obligations.
Allah knows best.