I take off his coat as he sleeps, then unpack my bag. At the bottom I find the slip of paper with Casey’s number on it. It’s against the rules to get involved, so I should throw it away.

Except . . . really, what harm would it do to pass on my stylist’s details? When everything else in her life is so hard, the least she deserves is a bloody good haircut. Before I change my mind, I text her the number:

Ask for Pepe and mention my name; he’s the best hairdresser I’ve ever had.

Within ten seconds she’s trying to add me on WhatsApp. I shouldn’t accept, but now I’m remembering the sadness in her small, round face. I want to know she’s all right, and for her to know that someone cares.

A minute later a message pops up:

Thanx am going to see if I can get Mum to make me an appointment before I leave Bristol at the end of the month when my treatment is over Sorry about before she worries a lot about me

I send a reply:

It’s fine. A lot of people do worry about dogs in hospitals but, honestly, the risk is incredibly low. Have a lovely night.

She’s typing a reply already. As soon as she’s sent it, I’ll end this conversation, firmly but kindly.

Can I send you the article Mr Porter asked me to interview you for, when I finish writing it

I shouldn’t encourage her.

The second half of the message appears:

It’s kind of important for my education to check I’ve got all the facts totally right.

Did she guess I’m having doubts? Casey’s had a lot of practice reading adults. And I guess if I do proofread her piece, I can also send her some science-based links that prove the world isn’t swarming with hidden carcinogens and silent dangers. She needs someone logical and reassuring in her life.

Sure. I’d be happy to.

She sends me a row of heart emojis back. I can already imagine my dad shaking his head at me. You’re as bad as your mum. And it’s true: I never can resist other people’s dramas.

Especially ones that distract me from my own.

Chapter 13: Dan

Tuesday 10 July

I wake up early and decide to treat Casey to breakfast in bed. She needs cheering up – there was a massive atmosphere between her and Angelica last night, but I was too chicken to ask what had happened.

‘Toast incoming!’ I say, knocking on the door and opening it at the same time, trying not to spill the orange juice or upend the tray.

She’s lying on top of the duvet – you can’t escape the heat, even this early in the morning – and for a few seconds I’m confused. It’s like a different girl has crept into her room during the night. Her younger sister? No, she’s an only child . . .

Casey opens her eyes. Yawns sleepily.