Does the dog wag the tail or the tail wag the dog? Such questions kept entering Arnold’s mind of late.

It started with a heightened sense of smell. Nose up, with a slow turn of the head to catch the scents whirling past on the sea breeze.

Brighton promenade, early morning. Mother in her wheelchair making sticky with an ice-cream cone, a white frothy milk moustache, sucking through the absence of teeth. Arnold is beside her. Nicknamed Arnold Lane after the Pink Floyd song by the giggling, sweaty boys in 5B. Now there’s a little grey around the temples, pinches of salt and pepper on the muzzle – a lollypop licked, orange onto his lips, gazing at two windsurfers gliding on the horizon. The smell of seaweed, an undercurrent of sewage, salt water drying on rocks, and, close by, some dog wet on the railings.

‘A bitch, possibly a Pomeranian,’ Arnold is thinking.

‘Cold now, I’d like to go home,’ says Mother.

‘Get you a cappuccino? It’d warm you up.’

‘No, home, please.’

Mother and Arnold, chair and walker, both quiet and thoughtful along the front, and then the long push home.

In their lounge, small and bent over, cramped by falling angles of bones into her seat, Mother watches Countdown with the sound turned up, an electric blanket, pink and new from Argos, £15.99, over her knees; an electric coal-effect fire; Arnold, scratching at a hole in his sweater, perched on the armchair beside her. On the seafront he’d noticed the smell of coffee, that’s why it had come into his head to ask her if she wanted one, but now he can smell something unpleasant.

‘You done a two, mum?’

Snores.

Investigating in the bathroom. No sign, but he flushes anyway. Soap scents, citrus at the back of the throat; ammonia too, so he coughs.

Thirty years before in the Mini-Traveller, its log cabin sides, Mother, Arnold Lane, and their Yorkshire terrier named Damien after the Omen film; Arnold had a thing for Lee Remick before she fell out of the playroom window. Mother at the wheel, Damien at the back with Arnold; fur soaked with seaweed.

Mother spoke: ‘you shouldn’t have let him roll in that stuff. He smells like a drowned rat.’

A whimper from Damien, Arnold’s hand on the bone at the back of Damien’s head, dog nose nuzzled into his chest. So close the two of them. Boy and dog, dog and boy.

When they arrived home, Arnold brought out the brush to calm Mother’s nerves.

‘Not so hard,’ she said. ‘You should always brush in the direction the hair falls.’

‘Like this?’ said Arnold.

‘That’s my boy,’ said Mother.

After the promenade, Mother’s nighttime snores have become damp and wheezy. It was cold on the front and the sea has settled on her chest, a trickle in her lungs. Her scalp is hot; red patches where hair has moved with Arnold’s stroking.

Arnold’s up, changing the sheets, dampening her face with a sponge.

‘Will you eat something now?’ he asks.

She shakes her head. He offers her a teaspoon of pink yoghurt.

‘Strawberry, your favourite,’ he says.

‘Don’t want it, too ill,’ she replies.

‘Aw, mum, you’ll be okay.’

‘No, son, this is it.’

‘Please don’t say that.’

‘I’m not stupid,’ she says.

A whine when he’s on the phone to the doctor. ‘Things aren’t so good with mum. Come and fetch.’

He hadn’t meant to say that. The ambulance men carry her out on a canvas stretcher with a red wool blanket pulled over. An oxygen mask too.

Medical chemicals in Arnold’s head making him dizzy. He asks if it’s all right to lie on the ambulance floor.

Cold on his shoulder and his head rattling on the metal floor by their boots, leather uppers; a cigarette recently stubbed out on a rubber sole.

‘Do you mind moving, sir?’

‘Have you got any water?’

‘We’re not a cafeteria.’

Not a cafeteria, the words sound alien. He falls asleep. Dreams. Running through a field, Mother rolling behind, he jumping over a small hedge, her wheelchair doing a Frisbee-flop a moment later.

‘Mum, mum,’ his legs twitching on the floor.

A rush of wind as the ambulance door opens. ‘Move it, please.’ And the stretcher passes a long shadow over his head.

In the ward, Mother’s chest creaks, and Arnold lies curled in a chair by her side thinking of a head being stroked, forever stroked.

He’s running with Damien: a game of throw and retrieve.

‘Go boy, go.’

Two jade eyes spying through the mesh of next-door’s fence. Dainty paws lower down, white trim: Kenneth, the tortoise-shell. Damien’s fur on high alert, arching his back, the ball desolate and unchewed in the middle of the lawn.

Kenneth springs on top of the fence, claws folded in, paws gripping like toy felt, slinking across the night sky, bottom up, tail like a fanning Yucca. Damien charging at the fence so he sticks, legs through the fence, held fast in stocks; and Arnold trying to tug him free.

Mother at the kitchen door. ‘Arnold, come in this moment.’

‘I’ll be back, Damien, sorry.’

Back as he promised, after a Fray Bentos, overcooked and black on top – Arnold never liking puff pastry ever since – and Damien is gone; Kenneth looking on, smiling wildly, pupils enlarged and speeding. But no Damien, even when Arnold cries his name through the streets that night.

Arnold mourned then, Arnold mourns now; Mother has passed away. A rose bush planted in the garden, yellow and pink, just as she requested. Smells sickly, like the Indian sweets they give him at the Kybher Pass, his nightly take-away. He’s planted a bush for Damien too, in case he ever comes back – ghost-like – to leave his mark, his marauding impression. His favourite bones still buried in the soft earth underneath.

After Damien disappeared, Kenneth fell out of a tree.

It’s raining. Arnold places mum’s urn on the mantelpiece, lies on the carpet, looks at the electric bars glow, and feels their warmth on his tummy. He closes his eyes and listens for a scratch on the bottom of the door. Tomorrow he’ll take himself for a walk on the seafront, buy an ice cream, and scatter the contents of the urn in the sea.