English Language Description

I'd really appreciate some advice and a predicted grade for this description. It's from Question 5 of AQA Language Paper 1: "Write a description of an old person based on the image."

Misery had taken hold of its pencil and sketched a portrait. Each line a crevasse of despair, each stroke thick with the agony of human existence. To glimpse at it for a moment drew the brine from my eyes. Pathetic. Pull it together. It's just a man. Just a...man.
But he wasn’t.
With each limb sewn from the threads of regret and remorse, every feature dripping with solitude and isolation, to behold him was a greater torture than death itself.
Arches of charcoal had been traced beneath the interminable pools of ebony darkness in his face. So burdened with the weight of survival were his eyebrows that they cast shadows over his eyes. Even if they had not acted as a sheath, there was no interpreting what lay within his soul. His eyes were a fortress, impenetrable and hostile. Nothing lay beneath the pristine surface, a barricade preserved for decades to renounce sympathy, to reject friendship. They stared back at me, unblinking. Not a flicker. They acted as mirrors, rather than doors to his person, simply reflecting the image of my own treacherous curiosity.
Look away.
Their hold on me was vicious. They had ensnared me with their darkness. I tore my eyes away to roam the landscape of his visage. Age had caressed his skin with its finger, leaving traces of the years past. It cinched his skin taut between the eyes yet slackened it on his cheeks. Flesh I imagined once supple had sunk, falling aimlessly from the structure of bone beneath. With it had drained his will to live, each breath now a wretched reminder that Death was unwillingly to sweep him in his eternal embrace.
The sun was the only thing that had ever kissed his cheek, staining it a deep chestnut, a coat wove from the labour and toil of his life. The hands of time had flecked his beard with snow, breaking the darkness of each inky fibre. The hairs crept down his neck, disappearing behind the flannel that concealed the rest of him from view.
Emanating from his being was the husky scent of tobacco, clinging to him like cheap perfume. Comforting yet sickening. Familiar yet disturbing. How long had I been staring? Too long. I could no longer see him. The liquid of grief now trickled down my own cheeks, leaving their salty traces to betray my internal wretchedness.
He did not move.
I watched an outstretched hand advance towards the canvas I had just been exploring. I didn‘t recognize it as my own. My thumb crept slightly behind his ear, resting on his jaw. My fingers sunk into the abyss of his beard as I cradled his cheek. The hairs prickled my skin, tiny swords of brandished steel to repel my touch.
We were still.
“Dad...” I croaked, the words barely leaving my parted lips.
No response.
“Don’t you know me?” I whispered, grasping his chin and lifting his eyes to meet mine. They regarded me with a petrifying blankness. “Don’t you know me?!” This time louder, shrieking, screeching. My pummeling fists rained down in a torrent upon his solid chest, each blow unfelt by his motionless body.

Arms seized me around the waist, hauling me away. Nothing could silence my yells. The hurry of figures bedecked in scrubs, the squeaking of crocs against the immaculately polished floor were but a humming in my mind. All I saw was his face. No longer blank but wrought with confusion. The disease had got him. Held him. Give him back. Give him back...