Two summers ago I was volunteering in the migrant and refugee camp in Calais when I met an Eritrean boy called Alex Tekle. He was 16, skinny, with a bushy head of afro hair, a bright smile and a look on his face of total exhaustion.

I was with a charity specialising in legal casework and so I asked whether he wanted help to apply to be brought to the UK through a legal route. He said: “Why should I bother? People always say they will help me, but no one helps me.”

He was clearly a boy who was used to being let down. He was all out of trust and who could blame him? He was living alone in a tent, in the cold and mud, in a foreign country.

Alex and I stayed in touch. After people were evicted from the Calais camp, he was sent to live in a town in the east of France where he was interviewed by the Home Office about his eligibility for transfer to the UK under the Dubs amendment, which sought to provide refuge for unaccompanied children arriving in the UK. He was refused, and so he returned to the north to try to cross.

We would talk on the phone most days. He’d send me voice messages, tell me what was happening and how he was feeling. I’d top up his phone so that he could call his mother. He was so eminently likeable.

‘There were brief moments of happiness and normality too.’ Photograph: Benny Hunter

I was worried, though. It was winter and he was a child sleeping outside in a wood and climbing on to trucks at night – anything could have happened. When he finally arrived in the UK, I felt relief. I thought that at least he might be safe here.

But the dream was not the dream. Nothing went right for him. He wasn’t offered the support that he needed and after being assaulted at his accommodation, he became homeless, sleeping on a sofa at a friend’s house in south London. Dejected, Alex’s self-esteem slowly fell to pieces and he turned to drink to alleviate his stress.

I became one of the few people Alex trusted, I think because I didn’t judge him or his choices. I understood the reasons for his actions – the underlying trauma from his journey and the separation from his family. He confided in me when he felt depressed or lonely and I’d send him pictures of my dogs and try to take his mind off things with funny stories.

The Refugee Council helped Alex and several months after he first arrived, he was taken into care in Croydon and given a social worker. But I think that at some point he lost hope. Without leave to remain and not in school or college, Alex had no stable ground from which to grow. There was a lot happening back home and he lost contact with his mum. His asylum claim and the threat of another rejection by the Home Office hung over him. The stress got worse and so did his depression and his drinking. Upset phone calls at 4am became a regular occurrence. There was a lot of anger and frustration too.

I remember one evening he called me in floods of tears, drunk and almost incoherent. He told me that he hated himself, that his life was “fucked up”, that he didn’t know what to do to fix it. He said that he didn’t want to be “Africa boy” – that he didn’t want to be a refugee – any longer. I tried to calm him down and to separate out his problems into manageable parts.

It was stressful to see him self-destruct from a distance. Slowly, there were some small positive improvements to his situation: I registered him for college, got him counselling sessions and he started to attend alcohol support meetings to reduce his intake. But by this point, he had been living in the UK for nine months and he was alcohol dependent, adrift, without permanence and without a happy future that he could imagine.

There were many desperate and difficult times then, in those last few months, that are painful to think back on and that I must keep private. But there were brief moments of happiness and normality too. One day, he and a girlfriend came around for pasta and we all watched YouTube videos together. I can picture him sitting in my kitchen happily playing with a light-up bouncy ball. Another time he surprised me with a watch that he’d bought me as a thank you gift. I protested but he insisted. It was important to him.

The last time I saw Alex, he had been hospitalised with hypoglycaemia – his blood sugar level had crashed after days of heavy drinking and because he wouldn’t eat. He was sober and lying in a hospital bed watching auditions for The Voice on his phone. I fussed over him a little and made sure he ate a sandwich and just stayed with him while the doctors did their tests. If I’d known it would be my last time with him then I would have stayed longer.

‘It’s six months since he passed and the pain of losing him is still raw.’ Photograph: Benny Hunter

A few weeks later, Alex was found dead. It’s feared he took his own life while under the influence of alcohol. He had just turned 18. I tried to distract myself with responsibility for the practicalities that come with a death. I became the person that everybody phoned – his friends, his family, his distant relatives. I had these moments of intense connection with strangers phoning from the other side of the planet. We shared stories about him and we cried together.

I helped to raise the money needed for his repatriation from 100 small donations and in late December, I went to Heathrow airport, alone, to say my goodbye. I watched as the plane carrying his body took off and flew him away. He arrived home on Christmas Day.

It’s six months since he passed and the pain of losing him is still raw. I think about him daily, about who he was and who he might have become, given the chance. I often wonder if I could have done more.

Alex was a bright light in my life. He was kind and he showed me love. I would thank him for that if I could.

In the UK, we are failing children who arrive here without their parents, seeking sanctuary. Their mental health needs are not being met, they are expected to navigate a complex and hostile asylum process while processing the loss and the trauma that many of them have experienced. Too often they are treated as difficult or unwanted – as a burden on society.

I believe that Alex’s life mattered. He wasn’t just a victim, he fought hard against his own demons and he believed in himself. There will always be young people like Alex, fleeing terrible circumstances and seeking a better future for themselves. The crisis is not that people move across borders, the crisis is in our collective response to that fact. We cannot turn away – we must do more, for Alex and for all the others

• In the UK, Samaritans can be contacted on 116 123 or email jo@samaritans.org. In the US, the National Suicide Prevention Lifeline is 1-800-273-8255. In Australia, the crisis support service Lifeline is 13 11 14. Other international suicide helplines can be found at www.befrienders.org.

• Benny Hunter is a writer and campaigner for migrant and refugee rights