Stuart Lawrence is the younger brother of Stephen Lawrence who, on 22 April 1993, aged 18, was murdered in an unprovoked racist attack. Stuart was 16 at the time and is now an educator and motivational speaker. In Silence Is Not an Option, his first book, he reflects on his brother’s life and murder and describes the tools he has used to help him live positively. Written for younger readers (aged 10+), the book aims to help them find their own voice and work towards a better future. Stephen Lawrence Day is held on 22 April each year to commemorate the Londoner’s life.

“You are my superhero”, you say of your brother and movingly write: “After Stephen’s murder, I asked myself what my big brother would want me to do. How would he want me to act?”
I was a younger brother and looked up to him – he was the stereotypical big brother in some senses: I thought he was better looking than I was, had better clothes. It was that admiration you have for an older sibling. We shared a room from when I was about six or seven. Before we went to sleep, we would have conversations about life, music, clothes, our hopes and dreams – Stephen dreamed of being an architect and I dreamed of being an actor. We were very close. That was what was so hard when he was gone because it was like, what do I do? It was like being in the dark. I realised the only way to get through it was to have some foresight into what he would want me to do. I knew he would want me to follow my ambitions and be the greatest I could be, so I charged on in his memory. I want to make Stephen proud.

The book is dedicated to your 10-year-old son, Theo…
Two things happened when he was born – [I felt] a huge sense of responsibility that life was no longer just about what I want and I also realised what my mum would have gone through when Stephen died; to have a child and for them not to be there any more – that was a daunting realisation. Theo reminds me of Stephen – he’s quick-minded, he’s friendly. I can see Stephen’s traits in him already.

You write: “My biggest failure after Stephen died was that I didn’t take some time to process my feelings about what had happened.” At what point did you finally process those feelings?
Quite recently. I think it’s a societal problem that we’re taught to have a stiff upper lip – you know, “You’re a “man, why are you showing emotions?” Those sort of stereotypes were there in my childhood. I think we’ve come a long way to understanding that it’s OK to cry, be upset - it doesn’t matter what gender you are.

What was it like in the immediate aftermath?
It was very difficult. I was so angry that Stephen was being portrayed inaccurately as a gang member in some newspapers, when in fact he was an A-level student and aspiring architect. I did have support from my youth club leader, which really helped me learn self-control. I lived with him for a year when I was 16 and it helped me grow up. Mentors like that are really important.

You explore the tools that have helped move you forwards. What are they?Resilience. Hope and optimism. I’m an optimistic person, which annoys my wife sometimes but what’s the point otherwise? I do try, even though it’s hard at times, to keep the eyes set on the little shard of light and that’s something I hope to pass on to my son. I also wanted to be a good role model to my younger sister, Georgina, like Stephen was to me, which helped me to try to be the best person I could. I almost got kicked out of my first secondary school because I was a bit unruly. Academically, I struggled – I didn’t find out I was dyslexic until I was 21 – but I was always creative and channelled that with help from good mentors. I used to want to be an actor but studied graphic design and became a teacher, then learned that I could help people by sharing my story in schools and organisations as a speaker.

You and your family have done immense amounts in campaigning for a fairer world. The Macpherson report was instrumental in defining race hate crime. How do you feel about the direction in which society is moving now in terms of racial equality?
First of all, I would like to pay my respects to Sir William Macpherson as we sadly lost him quite recently. [He died on 14 February.] It’s upsetting, as there wasn’t the acknowledgment I thought he’d receive through what he did. What’s most important is for each of us to ask the question – are you a good person? We all have a voice and an ability to use our voice for good. For me, there needs to be one clear message: we need to be able to just say “we are an anti-racist country”, then we could tackle all the systemic problems around race.

What’s a great book you read recently?
I’ve been reading David Olusoga’s Black and British – he talks about the end of the [second world] war and how we turned to our neighbours for help and support in the rebuild. This is another chance to rebuild. Now we’ve made the Brexit decision – how are we going to go forward as a country?

What’s next on your reading list?
I’ve just bought Unspoken by Guvna B, which is about toxic masculinity. I’ll be getting into it when I next have a day off – which isn’t until May.

Does your son Theo have any favourite books?
He’s really into Draw With Rob [by Rob Biddulph], where he can learn through a step-by-step process how to create something – our hallway is an art gallery of his creations. It really gives him confidence. I’m all about teaching people to be self-sufficient. He’s just finished Slime by David Walliams too.

What kind of reader were you as a child?
Huge. I used to go to the library on a Saturday, which was powerful growing up. It could be expensive otherwise. The Scholastic pamphlet [a children’s book club] was one of the highlights of the year. One of the first books I remember reading is The Adventures of Tom Thumb. There are so many distractions now for young people but I would really encourage them to read as it’s brilliant and gives your brain the ability to entertain itself.

• Silence Is Not an Option: You Can Impact the World for Change by Stuart Lawrence is published by Scholastic (£14.99). To order a copy go to guardianbookshop.com. Delivery charges may apply