I think SHAZAM
Makes me wonder who isn't family.
Honestly though I see it the same way I see Batman as in anyone who knows Clark Kent is Superman by Superman personally having revealed it to them before the world found out and such.
So that would include the original 7 to some degree atleast.
the martian manhunter and all the respective media has shown that , animated , smallville , supergirl etc how j'ohn are always involved.