After my brother died, guilt haunted me. Until I returned to where he died | Lynne Wallis

MMy older brother Stephen's descent into drug addiction began in 1969 in south-east London. It started with cannabis at school and progressed to LSD and amphetamines. By 1973, my 18-year-old, Jimi Hendrix-loving, Afghan coat-wearing brother was regularly using heroin and committing crimes to fund his habit.

I was 14 when Stephen entered the hell of heroin addiction. Like my parents, I was overwhelmed with shame in the pretty but stuffy housing estate we lived in in Eltham. Stephen's antics regularly made the local papers, most notoriously when he stripped naked, covered himself in yellow paint and jumped over the hedge outside our cute little house. He was on a bad acid trip and thought he was in a prisoner of war camp, the hedges had been turned into barbed wire. My parents couldn't take the gossip and we moved away in 1975, by which time Stephen had already served time in youth detention centres for burglary.

For the last six years of his life, Stephen was in and out of rehab. He almost died once before – he had a couple of near-deaths after taking heroin after a period of abstinence, not knowing that his body would struggle to handle the same dose. Either those horrors weren't scary enough to get him clean, or he just couldn't stop. I never got a chance to ask him. He was found dead in a bathroom stall at 24.

Since his death, I have been plagued by guilt over Stephen. Was it my fault that he was unhappy? What could I have done to help him better? Did my parents love me more than him? Why didn't I talk to him more?

Stephen was four years older than me, which our parents thought was perfect—Stephen was expected to look after me, just as my mother's older brother Jack had looked after her, but he never did. Despite our parents' best efforts to give Stephen enough love and attention after the birth of his little sister, my big brother did not cope well with my arrival. Family albums show him as a content, happy little boy, but after I was born, Stephen seems anxious and withdrawn. Home videos show me balancing on brick walls and singing “I'm the King of the Castle” while Stephen does a little sway and jumps off. This excessive caution irritates me when I think about the risks he would take later in life.

I have had a blessed, full life in many ways, but my brother's death remains the most defining event. My parents were understandably devastated to lose their only son, and I spent a lot of my twenties and thirties caring for them, feeling enormous pressure to compensate for what I will always see as Stephen's failure – I was living proof that they were not bad parents. How could I have made time for a family of my own? A more uncomfortable truth is that I was terrified of experiencing the hell my parents had gone through with my brother as a father. How would I have coped with a child like Stephen? I couldn't take the risk. Guilt about outliving siblings has also played a big role in my life. Why him and not me?

But when my mother died in 2018, everything changed. I was commissioned to write an article about a London hotel, and for the first time in decades I found myself in Leicester Square, where Stephen had overdosed in January 1980. With both parents dead and all duties and responsibilities for their happiness long extinguished, I felt a heartbreaking grief for the loss of my mad brother's young life, for the incredible waste and everything he had missed.

That day, all the guilt and shame I had shared with my parents dissolved as I was finally able to grieve 38 years after Stephen's death. I bought a candle and a miniature liqueur (he loved Cointreau) and sat next to where he died and held a little wake. It felt so good to experience loss and love instead of guilt. Why did I feel that Stephen's destruction was partly my fault? I was just a child when it all started. I didn't have the wisdom or life skills as a teenager to help him out of that situation. How could I?

When my parents were alive, I couldn't feel anything because I was so busy trying to compensate for their loss. I felt emotionally inadequate and at times full of self-hatred. It went something like this: If I didn't love him, I must have contributed to his self-hatred and was therefore partly responsible for his death. Now that I can finally grieve for myself, the guilt of having survived that haunted me for decades has disappeared.

I didn't understand then why Stephen was so bent on self-destruction, but I know now that it wasn't my fault. Stephen and I weren't close – it's hard to get close to an addict – but I cared deeply about him, and I really wanted him to get clean. I loved it when he called me by his nickname Lins in rare displays of affection. I allowed myself these precious little memories that day. It was a huge relief to remember something positive. Being released from guilt felt like being released from some kind of prison.

Stephen always said I was the clever one. I wonder what he would have thought of my life so far. I wonder even more intensely what his life would have been like if he had survived. He would be 68 today. I remember that as a young teenager he was a racing cyclist, a keen rock music lover and Monty Python fan. He also loved to draw. Who knows what he would have achieved if heroin hadn't taken everything away from him?