Answer
(Fatwa: 527/L=173/tl=1431)
According to Islamic teaching, one is asked to be good with one’s parents. If parents are rich and possess wealth according to their requirement, in this case son is not responsible for their maintenance. So, in the case mentioned above, when your father is receiving pension and three thousand rupees as rent, so their demand for fifteen hundred rupees for their expenses is not appropriate. If you cannot afford you should apologize with wisdom and politeness, however look after them time and again and fulfil their needs according to your capacity.
Allah (Subhana Wa Ta’ala) knows Best
Darul Ifta,
Darul Uloom Deoband