Is the aforementioned division of the insurance amount Islamically permissible, or should it be redivided?

If the amount is in the nature of an inheritance, such as blood money (Diyah) and employment benefits, it must be divided according to Islamic law. The grandmother is given one-sixth, and the remainder is divided among the children, with the male receiving the share of two females, and males being equal. It is stated in the Hadith that the Prophet, peace and blessings be upon him, gave the grandmother one-sixth, and Imam Malik mentioned that the grandmother inherits one-sixth as a prescribed share. It must be noted that matters of inheritance are serious and complex, and a mere fatwa is insufficient; rather, the matter must be referred to the Sharia courts. There might be an unknown heir, or wills, or debts that take precedence over the rights of the heirs.