However, Alec mentions others, and they include his father, whose sight-related power is "seeing to things". Maybe that means getting things done, or maybe he can see his way towards things, that is not specified. Then there is Alec's mother who "looks after things", which either means she takes care of them or maybe she sees things after they happen. Alec also has an uncle (it is unknown whose side of the family he is on) who sees the other side of every question, which probably means he knows the answers, and finally there is a third Bings sibling, a brother, who sees "beyond" things. (It is unknown what that means).
We never find out what they look like.
Alec's parents, and likely his uncle, are adults, so they have reached the ground. It is unknown whether the brother is older, younger, or Alec's twin, and therefore we don't know if he's grown down yet. He is likely not a baby as his ability is known, meaning he likely can talk.