Q. What change did the author noticed in the schedule of the grandmother on the day of the arrival?

That evening, the grandmother didn't pray. She collected the women of the neighbourhood, got an old drum and started to sing. For several hours she thumped the sagging skins of the dilapidated drum and sang of the homecoming of warriors. This was to celebrate the return of her grandson. The family had to persuade her to stop to avoid overstraining.
This was the first time the since the author had known her that she didn't pray. The next morning she fell ill.