Obligation of spending on parents and grandparents
Question

                Is it obligatory for me to spend on my father and grandfather? Please note that I am female.
Praise be to Allah.
    The child – male or female – is obliged to spend on his (or 
    her) parents if they are poor and he is rich. The obligation of spending on 
    them is indicated by the Qur’aan, Sunnah and scholarly consensus (ijmaa’). 

    Allaah says (interpretation of the meaning): 

    “And your Lord has decreed that you worship none but Him. 
    And that you be dutiful to your parents”

    [al-Isra’ 17:23]. 

    Being dutiful includes spending on them if they are in need. 

    It was narrated from ‘Aa’ishah (may Allaah be pleased with 
    her) that the Prophet  (peace and blessings of Allaah be upon him) said: 
    “Among the best of that which a man consumes is what he earns (by his own 
    efforts), and his son is part of that which he earns.” Narrated by Abu 
    Dawood (3528) and classed as saheeh by al-Albaani in Saheeh Abi Dawood. 

    Ibn al-Mundhir said: The scholars are unanimously agreed that 
    spending on poor parents who have no income or wealth is an obligation on 
    the child’s wealth. End quote. 

    A man asked the Prophet  (peace and blessings of Allaah 
    be upon him): Which of the people is most deserving of my good 
    companionship? He said: “Your mother.” He said: Then who? He said: “Then 
    your mother.” He said: Then who? He said: “Then your mother.” He said: Then 
    who? He said: “Then your father.” Narrated by al-Bukhaari (5971) and Muslim 
    (2548). 

    It is obligatory to spend on grandfathers and grandmothers on 
    the father’s side and on the mother’s. This is the view of the majority of 
    scholars (including the three imams, Abu Haneefah, al-Shaafa’i and Ahmad), 
    because the grandfather is also called a “father”. Allaah says 
    (interpretation of the meaning): “it is the religion of your father 
    Ibraaheem (Abraham)” [al-Hajj 22:78]. 

    And Allaah says (interpretation of the meaning): 
    “And marry not women whom your fathers married” [al-Nisa’ 
    4:22]. Here “fathers” includes the father and the 
    grandfather on both the father’s and mother’s side. 

    And Allaah says (interpretation of the meaning): 
    “For parents, a sixth share of inheritance to each if the 
    deceased left children” [al-Nisa’ 4:11]. Here 
    “parents” includes both the grandfather and the grandmother.  

    The grandmother is also called a mother. Allaah says 
    (interpretation of the meaning): “Forbidden to you 
    (for marriage) are: your mothers” [al-Nisa’ 4:23]. 
    This includes the mother and grandmother, according to scholarly consensus. 

    As the grandfather is called a “father” and the grandmother 
    is called a “mother”, they are included in the evidence which indicates that 
    it is obligatory to be dutiful towards one’s parents and spend on them. 

    See: al-Mughni (11/372). 

    Ibn ‘Uthaymeen said in al-Sharh al-Mumti’ 
    (13/498-499), in the chapter on spending on relatives: 

    The ascendants are those from whom you stem of fathers and 
    mothers.  

    The descendants are those who stem from you of sons and 
    daughters. 

    Then he said: 

    It should be noted that this topic is like the topic of 
    prohibition of marriage, and there is no difference between the father’s 
    side and the mother’s side. The ascendants and descendants are the same, 
    whether they are relatives on the mother’s side or relatives on the father’s 
    side. You are obliged to spend on them, but that is subject to conditions. 
    End quote. 

    In order for it to be obligatory to spend on fathers and 
    grandfathers, they should be poor and the child should be rich, because the 
    Prophet  (peace and blessings of Allaah be upon him) said: “Start with 
    yourself and give charity to yourself. If there is anything left over, then 
    (give) to your family. If there is anything left over from your family, then 
    (give) to your relatives.” Narrated by Muslim (997).  

    Shaykh Ibn Jibreen (may Allaah preserve him) said: If the 
    parents are poor and the daughter has wealth surplus to her needs, then she 
    is obliged to spend on her parents according to their needs, without it 
    detracting from her needs. End quote. 

    Based on this, the woman is obliged to spend on her parents 
    if she is rich and they are poor.