Maintenace

Sir, i am elder son in my family.my father is getting pension from E.B and taking care of my mother.recently, my mother hailed maintenance notice to me since i am working as govt .because of i am govt employee i neglected by her in property sharing. she gave 50% her property to my younger brother. and spent nearly 20 lackhs to build a house for her daughter 3 months back. In this circumstance i got one sale agreement from her for her rest of the property . she denied to do the registration hence i filed specific performance case against her and got judgment in favor of me. for appeal which are pending in court.in this circumstance , in order to retaliation for this suits she hailed maintenance notice demanding 50000/- p.m . will this maintenance notice/suit be legally valid/serious one now ? should i respond to this notice?she has own property for dwelling and younger son gives much amount and she is financially strong to conduct appeal case in court by spending much? should i give maintenance to mother while her husband getting govt pension.