Should he obey his mother by taking out a riba-based loan?
Question

                I am working in Tata Consultancy Services Ltd as a Team Leader for 2.3 years, Chennai. Alhamdulillah, I am earning a good salary and after withdrawing it, I keep some amount for Zakaat and Sadqah and the remaining I give it to my mother. She insists me to buy a home and a car for loan. I rejected it immediately because it involves riba (interest).

She is aware that Riba is total haram (prohibited), but she continues to demand and scold me because my other family members have car and own house. I said "Allah (swt) has prohibited interest in Islam". She said" I know it, but you have to hear (obey) what I have said". When I rejected the request, it made her very angry and sometimes she does not speak to me.

Please advice me what shall I do. We are living as one family and I dont want to leave my parents because I love and respect them.
Praise be to Allah.
    Firstly: 

    It is obligatory to obey parents except in matters that are 
    sinful, because the Prophet (blessings and peace of Allah be upon him) said: 
    “There is no obedience to any human being if it involves sin; obedience is 
    only in that which is right and proper.”

    Narrated by al-Bukhaari, 7257; Muslim, 1840.

    And he said: “There is no obedience to any human being if it 
    involves disobedience of Allah.”

    Narrated by Ahmad, 1098 

    Obedience to parents is obligatory upon the child in matters 
    that are beneficial to them and do not harm the child. With regard to that 
    in which there is no benefit for them or there is harm for the child, he is 
    not obliged to obey them in that case. 

    Shaykh al-Islam Ibn Taymiyah (may Allah have mercy on him) 
    said in al-Ikhtiyaaraat (p. 114): The individual is obliged to obey 
    his parents in matters that are not sinful, even if they are evildoers. … 
    This has to do with that which is beneficial for them and not harmful for 
    him. End quote. 

    Secondly: 

    With regard to what your mother said about it being 
    obligatory for you to obey her, that is true and it is enjoined by Allah, 
    may He be exalted. But if there is a conflict between the command of Allah, 
    may He be exalted, and the command of the mother or father in that they 
    command you to do something that is contrary to the command of Allah, the 
    believer has no doubt that what he should do is give precedence to the 
    command of Allah, may He be exalted. Hence the Prophet (blessings and peace 
    of Allah be upon him said:

    “There is no obedience to any human being if it involves sin; 
    obedience is only in that which is right and proper.”

    Narrated by al-Bukhaari, 6830; Muslim, 1840. 

    It says in al-Mawsoo‘ah al-Fiqhiyyah, 28/327 

    Obedience to other people – those to whom obedience is 
    obligatory – such as parents, the husband and those in authority – is 
    restricted to matters that do not involve disobedience or sin, because there 
    is no obedience to any human being if it involves disobedience of the 
    Creator. End quote. 

    Shaykh al-Fawzaan (may Allah preserve him) said: 

    Women are enjoined to obey Allah, may He be glorified and 
    exalted, and they are enjoined to obey their husbands and parents, within 
    the framework of obedience to Allah. 

    But if obeying a person such as one’s father or husband 
    involves disobedience of the Creator, this is not permissible, because the 
    Prophet (blessings and peace of Allah be upon him) said: “Obedience is only 
    in that which is right and proper)” (narrated by al-Bukhaari) and he 
    (blessings and peace of Allah be upon him) said: “There is no obedience to 
    any created being if it involves disobedience to the Creator” (narrated by 
    Ahmad). End quote. 

    Al-Muntaqa min Fataawa al-Shaykh al-Fawzaan, 
    1/265, 266, Question no. 161 

    Based on that, it is haraam for you to take out a riba-based 
    loan in order to buy a house – as you know, may Allah bless you – so you 
    should let your mother know that it is haraam for you to obey her in that, 
    and that her anger with you is as nothing before Allah, may He be exalted. 
    But you should treat her kindly because of the great rights that she has and 
    her status before Allah. 

    You have to be gentle with her and try to convince her that 
    no matter how much you may gain from something haraam, there is no barakah 
    in it and it will lead to bad consequences.  

    We ask Allah to make good easy for you where ever you are. 

    And Allah knows best.