Red and Serena (or Calem) do have dads that are alive, but it's not explicitly stated if they're still living with them.
If you interact with an item in Celadon's Department Store, Red monologues "Dad might like this!", while Serena's laptop was bought by her dad. In the postgame, Grace talks about Serena's dad and how she accidentally ran over him in a Rhyhorn race. It's played off as something silly, so he's likely fine now/wasn't killed by it.
