بسم الله الرحمن الرحيم
Pension is a contribution and gift from the government that the widow of a deceased person receives lifetime. Thus as per the government rule only the widow is entitled to receive it and the children of the deceased have no share in it. (Imdad al-Fatawa, vol. 4, p. 342, Kitab al-Faraidh; Mahmoodia, vol. 3, p. 193, Meerut)
Allah knows Best!
Darul Uloom Deoband
This answer was collected from the official ifta website of Darul Uloom Deoband in India.