And yet a few weeks ago, I came to the difficult decision that if she asked me for a kidney, I’d say no.
I know many people’s instinctive reaction will be to condemn me as heartless, even cruel.
But the truth is my sister is both feckless and reckless with her health.
She drinks, she’s used drugs, and she has three children by three men – all of whom have now been taken into care.
So I’m sorry, but I’m simply not prepared to risk my own health and the future of my own family to bail her out.
Recently, the case of a woman in Cheshire who refused to donate bone marrow to her dying brother became the subject of great debate, with critics from all sides branding her wicked and even somehow unnatural.
Who knows what family secrets lurk behind her seemingly selfish decision?