I headcanon that Five has a habit of checking on all the Umbrellas when they're sleeping to make sure everyone's alive and okay and accounted for.
Sometimes he just looks at them from the doorway and sometimes he goes to check their pulse, if they look too similar to the corpses he buried.
Claire and Stan quickly make the list of nightly rounds, at least when they're in the same city as five.
When Grace is born (Lila and diegos baby) they were confused (but relieved) that she slept so soundly and rarely woke them up crying. They still had to get up to feed her but she wasn't waking up screaming often
It wasn't until they found five sitting in her room, holding her and recounting some umbrella academy story that probably isn't suitable for children, that they realized it was cause of five.
Basically i headcanon that five would go and check on grace (to make sure she was like. Alive) and he couldn't just Leave if she started crying or seemed upset. So five would stay and hang out with her. He'd normally teleport away before Diego or Lila found him
When they found him the first time Lila just threw the bottle for grace at his face and said "well if you're going to break in you're going to feed her, I'm going back to bed"
Five did obviously but he grumbled about it (mostly cause he didn't like being ordered around by lila)











