forward-thinking / planning that does not cause any family turmoil

For starters treat Fredo as equal and don't!
Quote
Send Fredo off to do this -- send Fredo off to do that! Let Fredo to take care of some Mickey Mouse night club somewhere! Send Fredo to pick somebody up at the airport!

Whilst it is a delicate balancing act at least not exclude Fredo eg: The Godfather II - deleted scene
Sonny's daughter Francesca and fiancé Gardener Shaw
Sadly, it showed how Fredo was not part of Family matters nor Family business nor....And Fredo -- well -- Fredo was -- well --

Perhaps let Fredo sit in, at meetings Fredo knows to keep his mouth shut! unlike Sonny
Make Fredo feel important – even if as a figurehead....