He gave his infant grandson a car as a gift, but he did not give anything to his other grandchildren
Question

                My father owns a Jeep, which he left with me for four years, because I do not own a car. Six months ago, Allah blessed me with a baby boy, and I named him after my father. My father said: The Jeep is a gift to the new baby. My question is: I have five brothers, three of whom got married before me, and Allah blessed them with sons whom they named after my father, but my father did not give them what he gave me. Is this gift permissible?
Praise be to Allah.
      
      It is prescribed for the grandfather to be equitable 
      towards his grandchildren when giving gifts, just as it is prescribed for 
      him to be equitable towards his children. 

    
    An-Nawawi (may Allah have mercy on him) said: If the mother 
    gives a gift to her children, then like the father she should treat them 
    equitably in all the matters we have mentioned; the same also applies to the 
    grandfather and grandmother. End quote. 

    
    Rawdat at-Taalibeen, 
    5/379 

    
    Al-Haytami (may Allah have mercy on him) said in Tuhfat 
    al-Muhtaaj, 6/307 

    
    It is Sunnah for the father (and grandfather, no matter how 
    far the line of ascent reaches), to be equitable in giving to his children 
    (i.e., his descendants, no matter how far the line of descent reaches) and 
    his grandchildren. This has been stated by many scholars. However, other 
    scholars said that this equity is required only in the case of one’s own 
    children, not grandchildren,  whether that giving is a gift, a present, 
    charity or a waqf (endowment) or something else. If he is not equitable, 
    without any excuse, that is makrooh according to the majority of scholars, 
    and some said that it is haraam. The basis for that is the report narrated 
    by al-Bukhaari: “Fear Allah and treat your children equitably.” End quote. 

    
    Al-Mirdaawi (may Allah have mercy on him) said in al-Insaaf 
    (7/137): 

    
    It may be that his words about giving to children also 
    include grandchildren; this is strengthened by the words “division among 
    them should be in accordance with their shares of inheritance.” There may be 
    some among grandchildren who inherit. This is our view; it is also the 
    apparent meaning of the words of our companions, and it was given precedence 
    in al-Furoo‘. End quote . 

    
    What you should do is return this gift, and explain to your 
    father that it may cause some resentment in your brothers’ hearts, so there 
    is no need for that. 

    
    This idea is also supported by the fact that this gift will 
    in fact be for you, and you will be the one to benefit from it, not the 
    small child; hence your father has favoured you over your brothers by giving 
    it to you, and that is not permissible. 

    
    And Allah knows best.