The grandfather isn’t just holding the child. He has a, well, seatbelt on underneath his jacket. That is, a little seat that is attached to his body via a belt. (I plan to get one of these.)
I really liked how instep the grandparents were, and how the grandmother was holding the grandfather’s arm as he carried the baby.
I also liked how they were well outside the crosswalk, and the background action.
Such is life in Beijing.