He was the cause of his grandfather losing his Social Security pension; is he liable for that?
Question

                Ten or more years ago, my paternal grandfather was not working because he was old, and he was given a sum of money every year by Social Security. Then I registered a company in his name, and I registered employees too, then after that he lost the Social Security pension that he used to get every year, because of the company I registered in his name. Of course all the money earned by the company was for me, because I was a government employee and I was not allowed to open a company. Hence I had no choice but to use my grandfather's name, which I did with his consent. Please note that my grandfather did not understand anything because of his great age, as he had reached the age of nearly eighty years. Then he died (may Allah have mercy on him) approximately 5 years after the date of registering the company. After he died, I fired all the workers who had been under his sponsorship, and I shut down the company.

My question now is:

Am I liable for his pension during these five years that he used to get from Social Security, that was withheld from him by Social Security because of my registering a company in his name and changing his profession from pensioner to businessman?
Praise be to Allah.
      
      Firstly: 

    If 
    your grandfather had given you permission to do that, and he was in his 
    right mind and aware of the consequences that would result from his giving 
    you permission, then you are not liable for what resulted from that of his 
    being deprived of his pension. 

    Al-Kaasaani 
    said: The one who is given permission is not liable for the consequences of 
    an action for which he was given permission.

    End 
    quote from Badaa’i‘ as-Sanaa’i‘, 7/305 

    As-Subki 
    said: Approval of a thing means approval of what results from it.

    End 
    quote from al-Ishtibaah wa’n-Nazaa’ir, 1/152 

    Ibn 
    al-Qayyim said: The one who is given permission to do an action is not 
    liable for the consequences result from it.

    End 
    quote from I‘laam al-Muwaqqi‘een, 2/33 

    
    Shaykh Ibn ‘Uthaymeen said: A person is not liable for anything that may 
    result from an action for which permission was given; if no permission was 
    given, then he is liable.

    End 
    quote from Manzoomah fi Usool al-Fiqh, p. 15 

    
    Secondly: 

    If 
    your grandfather was not aware of anything at the time when you registered 
    the company in his name, then his consent is not valid, according to 
    sharee‘ah. 

    As 
    you were the cause of his losingof his Social Security pension, then you are 
    liable for his pension for the five years during which he stopped receiving 
    it. Liability usually occurs when damage is caused to something or its owner 
    is caused to miss out on its benefits. 

    
    Shaykh al-Islam Ibn Taymiyah said: Damage is of two types: damaging 
    something that exists or causing the loss of benefits of something that did 
    not come about when it should have been there.

    End 
    quote from al-Fataawa al-Kubra, 5/406 

    The 
    total sum of money should be distributed to his heirs in accordance with the 
    shares dictated by sharee‘ah. 

    And 
    Allah knows best.