Yasmin Alibhai-Brown: The sorrow of the silent witness

My only sister's carers seem nice, but she is retreating further into herself

Two beautiful young widows have been in the news this week. Christina Schmid, 34, whose husband, Staff Sergeant Olaf Schmid was killed last October while defusing a bomb, was invited to Downing Street. We know her face because she did not retreat into private sorrow as most of the bereaved feel they have to. Instead, she spoke out for soldiers and for better equipment, stood proud as the coffin arrived, wears her husband's medals and refuses to go away from the public eye. Her sorrow is her message and she has become the face of the war in Afghanistan, which she wants us to win.

Natascha McElhone is a talented English actress who starred with George Clooney in Solaris and has won accolades for her stage and screen work. Her stepfather is the journalism professor Roy Greenslade, her brother, a scriptwriter in Los Angeles. She married Martin Kelly, 44, a renowned plastic surgeon, had two children and was expecting a third when their charmed life went down, like a perfect yacht sailing contentedly and suddenly sinking deep into an opaque lake. She was filming in LA when a friend called to say Kelly was found dead outside their front door.

The news was unbearable and the future a blank, flickering scene. She needed to talk to the spirit of her husband, to herself, and to the unborn baby. To spare her young children further distress, her own tempestuous emotions had to be controlled. So she wrote dairies, wild, raw accounts, outpourings from a mind bewildered and in burning agony, interspersed with drippy bits and immensely sad practical lists; "write a letter to him, put in his coffin w cds, book, boys fav pokeman cards". Those scribblings, which became her net to stop her from drowning, have been published in a book, After You. Post-death desolation has found a remarkable voice.

Princess Diana – who died 13 years ago this August – seemed to speak to a nation that had freed itself from inward repression and outward decorum. She came from a class where both were expected and enforced. She broke free from all that and made it OK to talk about faithless husbands, horrid in-laws, self-harm, disappointment and that most taboo of subjects, death. In her wake, Britons allowed themselves to expose some of the terrible realities behind those twitching curtains and tied tongues. Revelatory books were published and pain was shared.

All too soon the old guard reasserted its values by mocking "misery memoirs" and those who bared all. Once more we are forced into secrets and lies, holding back, told to get on with life. Maybe it is because we are at war. When so many are dying, emotional expression is a sign of weakness, overt mourning an act of disloyalty. The two women above – without being conscious of it – are insurgents, defying society's orders to put up and shut up. Silence, we are told, is golden, the ultimate virtue, mature and noble, saintly even. It isn't any of that. To render us voiceless before death is inhuman. Callous too are those people who wilfully disconnect, opt out of conversations, indifferent to the distress they cause.

However hard it is, we must communicate constantly to remain sane. I am writing programme notes for a play going to Edinburgh based on the distressing story of the silent, black twin sisters whose tragic lives were recorded by the mental health campaigner Marjorie Wallace. They had a strict, taciturn, Edwardian father, lived in a white area, would not talk except to each other in their own strange language, went on crime binges and ended up in Broadmoor. Language makes us who we are.

My only sister was widowed last month. She is 11 years older than me. My father, who loved her best, had sent her over to England in the Fifties. Though she had been through crises which I was too young to know, in the early Seventies she was beautiful, a gifted painter, a glittering presence in Notting Hill, wore Mary Quant, played Bob Dylan, partied. By the Eighties there were signs that she was mentally ill and soon it took over, took the sister I knew. She talked less and less and sometimes not at all.

Her husband, Mick, a social worker in the Welsh valleys, the most compassionate person I have ever known, took care of her. Only he never shared with me what her diagnosis was or details of her treatment. When dying of cancer, he was most worried about his wife. I wish I knew more than I do. And now he is gone, much missed and mourned.

At the funeral my sister couldn't cry, was locked in her own impenetrable world, except for flashes of lucidity – when she heard the music at the crematorium she sat up and said: "Mahler". Talking to an old friend from the exciting days, she asked about others they knew. Her grown-up daughter, very close to Mick, stopped speaking to me two months ago, for reasons not explained.

My sister has gone into a nursing home in the valleys, far from the surviving family. Her carers seem very nice but she is retreating further into herself. It breaks my heart. I hold the stories of our lives, the bond between us. I have dreadful dreams – a snake is approaching her, she has no voice to cry out and it strangles her. My grieving niece puts down the phone and was enraged when I wrote a sober and frank letter to her partner.

If I have done wrong, failed, words could help make it right between us. Maybe I didn't do enough, maybe they blame me for her condition. I just don't know. I lost my only brother too this February. He too was uncommunicative, always furious with me for writing openly about the family. Now it is too late. My father cut me off from when I was 15 to the day he died. Only my mother was different, open and emotionally honest.

Reading McElhone's book made me wonder what my sister would write if only she could. She can't. I can. It may have been the saving of me but it has left me alone, condemned to separation, like many others who will not stay silent nor consent to the deliberate use of silence, even in this age of emotional austerity.

y.alibhai-brown@independent.co.uk

For further reading: After You, by Natascha McElhone (Viking, 2010)