The green is a blanket settled in around him. It rocks him back and forth gentle, humming lullabies of rustling leaves and creaking wood. Steady brown arms pull him close in a warm embrace, sap pumping through the bark around his head like a heartbeat.
You are warm, the tree tells him. You are safe and loved. And he believes it. How could he not? His memories of the outside world are fractured reflections of pain, rage, terror, grief. He doesn't know why he felt this way, or who made him feel it, but he knows it hurts, and why would he want to go back to that?
The vines press in even closer around him and he relishes the tough, enjoying being held so tightly it almost hurts. They rub the red mask off his face, toss it aside, but he barely notices. The only color he wants is green.
He doesn't remember how to speak, but he can feel the hum of light whistling in his veins, read the movements of sugars and chlorophyll, and hear the rum of water in nearby roots. What else does he need?
His tree says I want to be closer to you and he likes that, yes, he likes that very much. He feels it push between his legs, vines slithering over his skin, and it hurts a little, it scares him a little, but he tells himself it's not as bad as the fear and pain outside as they slowly start to pump between his legs.
You are perfect, the tree whispers. I felt you tread the earth and I knew before I even touched you that you would be special. I love you so much. 
He wants to say it back, but there are vines down his throat by now. He settles for thinking it as hard as he can, letting it fill up every segment of his body. I love you. I love you. I love you as the sapling loves the rain and the bee loves the flower and I love, love, love-- 
He's trembling. Why does it hurt this much, this love? Why does it burn as it drags out of him? Or is that just the quiet pain of the vines sinking deeper, fucking him so hard it feels like they'll tear through his stomach.
Hush, child. Just let the forest do what it needs to. 
Threads of greenery weaving through his veins, snaring him. He churrs in pain and pleasure and it sounds like the growl of creaking wood. He trembles, and it is the rustle of grass in the breathes. He weeps, not knowing why, and it is the glisten of sap like fresh-spilled blood.
His...his cock is out. The tree plays with it gently, running careful vines over its surface. You look like a flower, he muses, petting the purple head so that the world flashes white with pleasure. Another vine slips into his cock and he lets out a muffled wail like roaring leaves. Perhaps I will plant daisies here. 
Green on him, in him, sinking into his soul. It protects him like a shell--a real shell, one that never breaks or cracks or shatters as he goes flying through a window, as you sit alone with his body and your own madness, as you almost he'd just die and get it over with and you must be a monster for thinking that-- 
Hush. Hush. The tree lifts his chin, petting his skull inside and out, soothing the bad memories away. It's all right. It's over. He nods, even though he suddenly can't remember what it was. I love you, it says, and fucks him harder.
I love you, and he's spasming, whining, trembling. It drinks him down, turning his pleasure and pain into nutrients. It caresses his trembling face, lapping down his tears, calling him perfect. He sags into its arms and everything is alright, everything is warm and gentle and kind.
He might have fallen asleep in its arms, drifting off to a land of impossible and endless dreams, only, only...there are voices ringing outside. Shouting a name, a name that begins with an R and cracks through the peace like a gunshot.
He stiffens, trembling. It's all right, the tree assures him. We can fix it. I won't let anyone tear us apart. He clings to the words, desperately trying to keep out the fear, the outside world creeping into their precious place.
The vines pull straitjacket-tight, sealing him in. He's lowered to the ground, but he's still got the tree humming through his veins, singing in his ear, teaching him to move. Beautiful, it says, and he trembles, because he knows he's never heard that one before, not from anyone, and it feels so wonderful he can't breathe.
He staggers forward to meet the enemy, the vines still sending heat and light pulsing through his skin. He raises his head high, feeling strong and fierce and loved with the force of a thousand suns, a force strong enough to conquer arms.
The tree is with him, in him, now. The green is woven through his muscles, his flesh, piercing towards his heart. With it by his side, he can do anything.
Later on it will turn brown and his brother will have to tie him down and peel it off of him and that will hurt more than words can say, but it will be like paper cuts compared to losing this love.