Before my 19-year-old son di3d, he donated his heart to an 18-year-old girl — after the transplant, her mother handed me a letter from my son that began, “Mom, there’s something you need to know about her.”

Why he did not tell me.

The letter says.

***I didn’t tell you because you’d have had to decide something. And you had enough to decide. You were selling Nana’s rings, Mum. I saw the receipt.***

***And because I thought if I told you while I was still here, you’d have done it for me. You’d have been nice to her because I wanted you to be. And that’s not the same thing and it wouldn’t have lasted.***

***So I’m telling you after. When it’s only about you and her.***

Nineteen years old.

He worked out that a kindness done for a dying boy is not the same as a kindness done for its own sake, and he arranged the whole thing so that I would only ever have the second kind available to me.

And Dr Selvan, who I went to see in the June, because I needed to know whether my son had been talked into something.