My sister wasn’t dead when the police broke into her flat on a cold night three years ago. Not quite dead. She wasn’t breathing or responding. She was lying on her hall floor, cold and still, but there was a tiny twitch in her jaw. It was barely perceptible, but it was something.

I waited outside with police officers who wouldn’t let me near her, then we followed an ambulance to A&E. The doctors told me she was hypothermic and they were trying to warm her up; when her body reached a normal temperature, they would try to get her heart to start. They tried, but it wasn’t working. They let me hold her hand while they tried for the last time. And then she died. She was 39.

The darkness inside her, the self-belief beaten out of her by the people supposed to hold her close, got her in the end

Jenny was beautiful. She was tall and slender with big gorgeous eyes and silky hair. When we were children we spent a lot of time laughing uncontrollably together over anything that came our way and, often, at the absurdity of our situation. As children who were beaten and abused by a violent father and neglected by an alcoholic mother, who when drunk encouraged his rages and when sober ignored them, humour helped us. It’s what bonded us as adults, too.

You don’t get out from that kind of childhood unscathed. I was luckier. I have a home, a family, love, work, friendships. Jenny worked all her life, always in the voluntary sector. She bought her flat alone, she supported herself, she worked hard. But she struggled. The darkness inside her, the lack of self-love, the self-belief beaten out of her by those two people who were supposed to hold her close, got her in the end. She left work, got into debt, stopped eating, drank too much. She went so far inside herself I found it hard to reach her; other people found it impossible.

The coroner’s verdict was accidental death, but if I’d written the death certificate I’d have recorded it as murder: our parents, her past, catching up with her and killing her in the end. But hard as her death was to bear, I couldn’t have known there was worse to come.

We had been estranged from our parents for many years. We knew my father had died but, at the time of Jenny’s death, I had no idea about my mother. Years earlier, I had written to tell her she had a grandchild. Twice. I received no reply. Now I wrote to tell her that her daughter had died. Again, I expected no reply but I did receive one from a cousin, Alan, who had been placed in legal guardianship of my mother, who was now living in a care home and had dementia. He considered it better not to tell her of Jenny’s death, as it would upset her.

Alan and I exchanged emails and phone calls, and met up. I had buried Jenny but, as she had not left a will, I had no legal right to wind up her estate. I couldn’t sell her flat, or dispose of her few belongings, or settle her many debts. Alan helped me get permission from the estate to do those things.

For a short while it seemed as though I’d found a new family. Suddenly, I had new cousins. As well as Alan, others wrote to me and Alan’s father is still in contact.

But it became clear that, as my mother had outlived her daughter, Jenny’s estate would go to her. Meanwhile, my father, in a last act of malice, had left their estate to Alan and the other cousins, strangers to me and Jenny.

I was terrified of my father until the day he died; I wasn’t waiting for a payday

I told Alan about our family history, and that it would have horrified Jenny that what little she had should go to her mother – and then to these strangers rather than to me or, more importantly, to my daughter, Hazel, whom she dearly loved and was loved by in return. He agreed and said he couldn’t imagine the other cousins would think it right that they should profit from Jenny’s death.

My mother died in 2016. I wrote to my cousins, explaining our past, telling them who Jenny was, who she loved, and asking for assurances that they would not claim Jenny’s estate – that they would exclude it from my mother’s.

I didn’t receive a single reply, only demands from their solicitors that I hurry up and hand over Jenny’s money. I hired my own solicitors to write to the cousins on my behalf, asking that they sign a deed of variation, to exclude Jenny’s estate from that of our mother’s.

I made no claim on my parents’ estate. Again I received no reply, only chilly letters from solicitors asking for updates about Jenny’s estate. These responses felt like slaps in the face, of a piece with the violence Jenny and I had endured as children.

Of course, people argue that you should be able to do what you like with your money. But Britain is odd in this respect: in other countries, parents are expected to provide for their children’s wellbeing in their wills.

I didn’t want money, I wanted justice. In particular, I wanted to ensure my sister’s estate didn’t go to strangers. But, as counsel coldly if clear-headedly pointed out, I had no leverage.

I received an offer from the cousins’ solicitors. It proposed adding up the values of both my mother’s and Jenny’s estates, and dividing the total between the cousins and me. It read like cold arithmetic, ignoring the fact that I wanted my cousins to do the right thing.

In the end, I decided to accept the offer. As a result, I received a portion of my mother’s estate, which included some of the money Jenny left at her death. Both sides incurred legal bills, and Jenny’s flat sold for far less than the market value because it had a short lease. It turned out that the extra bounty they had counted on added just a few thousand pounds to their haul.

Blood isn’t enough. It doesn’t guarantee kindness or decency or a good heart

At the end of the summer, there was a strange twist to the tale. I received an unexpected letter. Alan wrote after a long silence, apologising for being out of touch because, as he put it, “the situation of trying to reach an agreement over your mum’s estate had become quite exasperating”.

Then came the kicker: “My opinion about Jenny’s estate has never changed and due to this I am enclosing a cheque that I believe covers the portion of Jenny’s estate I have inherited.”

I hadn’t expected this. I had been baffled and hurt by his unexplained silence and assumed it had its own sickening eloquence. I was glad to be wrong.

I wrote back thanking Alan: “It makes me feel slightly better about the horror of the last couple of years that one member of the family can do the right thing and behave with decency, and I appreciate that.”

I never had any expectations of an inheritance from my parents. They weren’t rich and, besides that, they had gone for decades without making the slightest attempt to contact their two children, despite knowing where we lived. I was terrified of my father until the day he died; I wasn’t waiting for a payday. I would have liked a mother who’d support me through pregnancy and work, and a dad who’d champion my studies or help me move house, or tell me I was beautiful, but that ship sailed long before they died.

What has left my daughter with a sense, not of joy in a newfound family, but of profound disgust, is the greed and callousness of the cousins who saw her aunt’s death as an opportunity to squeeze more money from a family they barely knew.

So I have a responsibility to show Hazel that there is another way of being a family. There’s her mum and dad, obviously. And her dad’s family. But there are also her friends, and our friends. Blood isn’t enough. It doesn’t guarantee kindness or decency or a good heart. She’s learned too young a lesson I learned at a similar age – that a family can be a very cold, hard place in which to grow up.