There's a reason why my choice for the best screen mom of all time is Jaya Bachchan in Fiza, and the reason is this scene. (Before you ask, no, I haven't seen Hazaar Chaurasi Ki Maa, so I can't comment on that one.)
Her son was lost years ago during some communal riots in the neighbourhood - he grows up to become a terrorist. His sister finds him and brings him back home, and it seems for a while that he has left that life behind him. His mom, who is learning to smile again after so many years, is reverting to her old playful self.
And then, he gets into a fight with some local goon who harasses his sister and goes to town on the guy. The incident also precipitates his revelation to his mother and sister about having joined a terrorist group again.
Watch Jaya Bachchan's eyes as she takes all this in. She dies soon after (by her own hand, if I remember correctly), but the actual time of death is in that scene. Watching the light go out of her eyes when she sees what her son has become is among the most haunting moments in this interesting yet flawed work.
ps: Soon after Jaya dies, there's a song picturized on Asha Sachdev who plays Jaya's flirty neighbour Ulfat. It goes Na leke jaao mere dost ka janaaza hai and is sung by Jaspinder Narula. A lot of the other songs in the movie became popular, but this is the real gem in that album.