What is the best way to handle the challenge of dividing a cash gift invested for grandchildren, after the donor became unable to retrieve it due to dementia, knowing that this gift was not equally divided among all her children when it was given?

Justice must be observed among children in gifts and endowments, but justice is not required between children and grandchildren, unless the gift to the grandchild is a ploy to favor a son, in which case it is forbidden. If your mother has other grandchildren, Imam Ahmad’s school of thought dictates that justice must be observed among them, so the wealth is divided among all grandchildren, with the male receiving the share of two females. It is not permissible to dispose of the assets of someone afflicted with dementia except for their sustenance. It is recommended to rectify the situation by distributing what the mother gave to your children in the manner mentioned.