To take the retirement pension

Q: O shaykh! May Allah prolong your life and bring us together in Jannah (Paradise)! My question is that I am the Shar`y (Islamic legal) attorney of my father-in-law who died on 04/02/1416 A. H. (may Allah be merciful to him). He left a wife and sons and daughters who are all of legal age and married. The deceased used to receive a monthly pension of eight hundred Riyals for having previously served in the government. Due to his old age, he entrusted me with a general power of attorney and asked me to receive this sum on his behalf. I therefore opened an account in my name in the same bank where the concerned pension is received. I asked the bank to transfer the pension to my account on a regular basis and I started to receive money from this account to give to my father-in-law the sums that he would need. Then my father-in-law died as I mentioned earlier, but his pension still goes monthly into my account. I asked the bank officers about the procedures that have to be taken in the case of the death of a pensioner and they answered the following:The total value of the inheritance has to be counted, whether his wife receives any specific income should be investigated, and whether the deceased has young children. As mentioned above, the sons of my father-in-law are all of legal age and married. On the other hand, my mother-in-law receives a pension which exceeds that of her deceased husband and in this case the wife is given the right to choose to receive only one of the two pensions. I, the attorney, asked some scholars in my city, Al-Madinah Al-Munawwarah, about the matter. Some of them said that a pension is (Part No. 23; Page No. 475) the Shar`y right of the deceased because its value has been deducted gradually from the person's salary throughout the period of his service. Some other scholars refrained from answering and mentioned that this question has to be asked to senior scholars.My question is whether I have to continue receiving the mentioned sum and deliver it to the wife and children of the deceased or if we have to give it in Sadaqah (voluntary charity) on behalf of the deceased? It may be worth mentioning that the deceased used to support some orphans through the Islamic Relief foundation. These orphans are still supported by the money of the deceased and this support will continue, if Allah wills, even if his pension is terminated.Please provide us with your Fatwa. May Allah reward you.