After deducting the funeral expenses of the deceased, the rest of the death compensation shall be evenly distributed by the first heir in order.
The first order includes parents, spouses and children.
Your mother has dissolved the marriage relationship with the deceased, so she is no longer the heir, so she has no share, but you and your sister (if born to your mother and the deceased) have a share, and the other party can't get all the shares alone. It is suggested to bring a lawsuit to the court to divide the death compensation.