At 6.10am on Tuesday 14 August 2012 my eldest child drew his last breath. I have to look up the time and date because my brain refuses to acknowledge this information, it’s automatically sent to the spam file as dangerous. I find my brain’s attempts at self-protection rather touching in the wholesale carnage that is grief.

The death certificate states who, where, when and why – number nine on the list, cause of death: I (a) medulloblastoma. Medulloblastomas are a group of cancerous brain tumours, the commonest in children, and David, known as DD, was diagnosed with his during October half-term in 2007, aged 11. What his death certificate doesn’t tell you is the quality of his life up to the point of death, his quality of death if you will, because that is a subjective judgment. Many people fortunate enough not to be familiar with death assume all deaths must by definition be “bad”, but as a bereaved granddaughter, daughter and, now, mother, I can tell you that is not true.

He lived as long as he possibly could because his quality of life was so good – entirely down to palliative care.

My biggest consolation in grief and my greatest achievement in life is to have fulfilled the wishes of my child – emotional, physical, spiritual – as he approached death during the last three months after his terminal diagnosis. I do not have guilt or questions and I know full well how lucky I am to be able to say that. I have met families who did not have this and they tell me they will never recover and, knowing what DD’s good death means to me, I believe them.

You might ask if my son would say the same thing about his death, were he still alive. We had many honest conversations about what was happening to him during his treatments and he knew and had accepted he was going to die; he was at the meeting when the scan showed the cancer was clearly incurable. I can only answer by describing what he achieved in those last three months and his last lucid words: “I love it here.”

He was lying in bed and gazing out of his bedroom window, his cat on the bed, into the treetops of a Dorset woodland. He was calm and comfortable; his major symptoms of seizures, sickness, dementia and pain from the satellite tumours that had spread from his brain all down his spine were all under control with a barrage of medication and equipment.

Up until those last four days in bed, a good day for him involved cooking, studying and flying birds of prey, partying with friends, following environmental issues, watching movies and playing and arguing with his brother and sister. Nothing was done to him medically during that time that would interfere with his loves. This means his medical team, consisting of a Marie Curie nurse at night, district nurse and GP (the latter two with end-of-life training from Gold Standards Framework) with a battalion of experts available 24/7 by phone from Southampton general hospital, our main treatment centre, had done the polar opposite of fail. They had triumphed and I hope every single one of them takes enormous professional pride in having done so. Death doesn’t have to mean failure.

A couple of years after DD died I was asked by the Brain Tumour Charity to talk about how we managed his death at home. I was still raw and very unsure whether I would be able to deliver, or if it was useful, but my misgivings were overturned by overwhelming feedback to the charity: parents facing the end of life of their child said they had no information and felt completely isolated.

We too had left hospital after our terminal diagnosis with no written information and no link to the national charity, Together For Short Lives, which supports families with children and young people with life-shortening conditions. We had thought DD’s cancer would be cured. At diagnosis he had a very high percentage chance, so we did not think we needed palliative, let alone end-of-life, care.

Like everyone else I knew, I thought that engaging with this service meant I would be giving up on my child and we would be cowards to stop treatment, that it was all about fighting, which is why, in my humble opinion, the Charlie Gard story was so emotionally complicated. In fact DD was having loads of treatment at home in those last three months; it just wasn’t curative and we had done the opposite of give up on him – we had hope for life every day. I now firmly believe he lived as long as he possibly could because his quality of life was so good, which was entirely down to palliative care.

I gave the speech and the hugely positive reaction by parents and health professionals inspired me to continue. It was called Follow the Child because that was what a bereaved mother, whose child had died before DD, told me to do. I realised if she could do it, I could do it, and if I could do it, other parents listening to me or reading my words could too. The key is to plan well in advance, when you’re not crisis-stressed – as you do with a birth plan – planning for life up to an inevitable death.

However, it is clearly disgraceful that a third of local commissioning groups nationally do not have anything out of hours or at weekends for families – DD didn’t stop dying then. You do not have choices at the end of your child’s life and the new Nice (National Institute for Health and Care Excellence) quality standards are very clear that families need those services. A&E would have been fraught and it’s astronomically more expensive than being at home. I beg the government to commit to developing a national children’s palliative care strategy for England; there would be uproar if maternity services were similarly 90% under capacity for key staff such as midwives.

For the book, I consulted four other sets of parents who were passionate about improving end-of-life care. We have laughed and cried and then needed the reassurance of experienced social workers, palliative nurse and paediatric palliative consultants to check our efforts. I only regret that I was never able to meet their wonderful children. DD would have been proud of us and might quote his favourite Buddhist-inspired phrase: “Life is suffering, but every second of life is a miracle.”

Follow the Child by Sacha Langton-Gilks is published by Jessica Kingsley (£14.99). To order a copy for £9.99, go to guardianbookshop.com or call 0330 333 6846