About 30 metres from where they crossed the road is an overhead bridge.
But Mr Tan Tiong Him, 66, opted not to use it as he felt climbing the stairs would be too strenuous because of his age.
He proceeded to cross Eu Tong Sen Street near the New Bridge Road Bus Terminal with his young grandson.
The decision turned to be fatal for eight-year-old Galen Ong Zi Jie.
While they were crossing, a car hit them, and the impact flung the boy to the middle of the road about 10m away.