Are the lump sum paid upon retirement and pension part of the estate?

My father died and I distributed what he owned in the form of cash, according to Islamic teaching. But there is some of the wealth that is not in our possession, as follows: he had a lump sum that was to be paid out when he died, because he was a retired employee. Should we distribute it when we get it, as that is not possible at present? What will happen if one of the heirs dies before that money is acquired? From the time he died until now, there are also pension payments that have been received. Should that be distributed in accordance with the shares of inheritance? Please note that the state will divide the pension among the heirs in a different manner, for example it will be distributed to his wife and children, but not his mother. He also has some money that was previously deducted from him every month for ten years, like a cooperative savings group, and when the money reached a certain amount it was to be given to my father, but he died before it reached that amount.