I am recently retired, I will get a handsome amount e.g. G.P.F. gratuity, General Insurance etc., Can I invest this amount from where i can get monthly income or to fix for particular time. I will not use this amount in my purpose I will use these interests into giving the bribe or to my help my Sister, whose husband is not with her and having to younger daughter, surviving with difficulties and having responsibilities to marry her daughters.
Jazak-Allah

All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His Slave and Messenger.

It is not permissible for you to invest your money, whether it is a gratuity or anything else, in a Riba-based bank. This involves consuming Riba and cooperating with the bank in sin and aggression. However, if the Muslim does not find an Islamic bank to keep his money in, it will be permissible for him to open a current account with a Riba-based bank for a need. However, the interests he obtains from that must be spent on the public interests of Muslims or given to the poor and needy people as charity. He is not allowed to use any of these interests for his personal benefit. For further information, please refer to Fatwa 81626.

Similarly, giving bribe is a grave sin, particularly when it is paid to obtain something a briber does not deserve. As to the bribe that a person pays to get his own right or eliminate injustice or harm from him, it is permissible – according to the majority of scholars – and the sin will be on the bribed person only. For further information, please refer to Fatwa 83777.

However, it is not permissible to use Riba (the interests) in giving bribes; rather they should be spent on the public interests of Muslims as stated above. Therefore, we advise you to invest your money in a lawful channel, such as with Islamic banks or Sharee‘ah-approved Mudhaarabah. In this case, it becomes permissible for you to benefit form the profits and support your sister or anything else.

Moreover, we remind you that there is no blame on you in obtaining gratuity when it is stipulated in the contract or approved by custom. But it is not permissible for the Muslim to contract with the company on obtaining a gratuity through the prohibited commercial insurance even if the employees have not paid the insurance installments because this constitutes cooperating with the company on committing a prohibited matter and agreeing on it.

Nonetheless, if the employees signed a contract with the company to get a gratuity while they do not know anything about the company's insurance for them, it would be permissible for them to take the gratuity, whether received from insurance or elsewhere. That is because they are not responsible for the money that other people earned when the latter pay it to them because they deserve it in a lawful manner. For further information, please refer to Fataawa 91039 and 82891.

Allaah Knows best.