Soo...
The concept Shattered dream but in dreamswap.
Umm, so something crucial happens in the plot that causes nightmare to believe that to get dream back to how he was he'll have to understand how dream feels.
So nightmare stupidly eats a positive apple
Sinking his teeth into the apple. A strong compulsion flows in his marrow. Ravenously he tears into the apple. Pain constantly growing, nightmare wants to stop but he can't. Biting the cursed apple for the last time, Pain blooms from his back blood flows from his maw staining the grass red. Wing burst form his back. Lilac feathers flying everywhere. Looking up he sees dream looking at him in horror, tears streaming down his face. Nightmare smiles a sickeningly sweet grin. He strides forward.
dream stumbled back and trips falling on his arse. Dreams feathers fall off and his wings dissipate in a golden cascade, slowly the feeling of sickening positivity fades form his aura.
"Well brother do you love me now" nightmare purred out.
Dream sobs in the background.
Please comment if you write this.