For me that's capturing special moments, interactions or views in urban environments to tell a story through the photo.
Is it random pictures of strangers?
It can be, but it needs to have a story, something special in the interaction or the environment, I don't consider that guys taking photos of young women in the street without consent just because "they are beautiful" is street photography (but weirdly that's one of the most popular photo style on social medias...)
Even more for babies, facial muscles make all the face look different when eyes are open or closed. Maybe he can but he thinks that it wouldn't look right, reworking a whole face is immediately a lot harder.