A player would like to cast the 'Dream' spell on an ancient statue of a petrified hero. Thematically this is wonderful, sure - but does it work by RAW?
Here are possible answers we discussed / lacking backing:
Rule of Cool: A creative and fun use of the spell! Advances the plot. Not abusable. Why not? Find out if statues dream of stone sheep
Incapacitated people sleep... why not statues?: As 5e lists 'petrification' as being incapacitated ('no actions / reactions') and is 'not aware of the space around them'. Sleep = 'unaware of time's passage'. Thus all petrified creatures default to a place resembling sleep. Besides, the Dream spell is powerful magic - this isn't just shaping biological dreams, it is providing a telepathic uplink between 2-3 creatures for an eight hour span.
Bricks Do Not Dream! One cannot attain REM-state nor entertain any neurobiological capacity whilst granite. As solid stone, one is not Han in carbonate! Just like an elf that can not sleep, neither can a statue. Even if you successfully cast a Sleep spell on such a person-statue, such a creature cannot even entertain this rest-state unless Greater Restoration is used.
We are sure that that the first answer is by FAR the most magical, thematic and/or fun (R.A.F.). As a DM, I also fear that the last answer is most logical and/or closest to 'R.A.W.' Still, we would like your collective perspective on this, with thanks.
Long story short:
Is there any ruling, be that a tweet from Mr. Crawford (or other such source), that might suggest that Dream can be used on petrified creatures?