Omar Farah, who is 20-years-old, was arrested and spent a month in a young offenders’ institution, before he became homeless and admitted to regularly smoking cannabis.
But double Olympic champion Mo, 29, has stuck by his brother – who was present to watch his elder sibling storm to victory in the men’s 10,000m final - and given him his full support as he attempts to turn his life around.
Omar said: “The experience of being in the young offenders’ unit made me never want to go back.
“Mo’s success has inspired me to do something with my life. I don’t want to doss around and get into trouble with the police.”
Omar was caught up in the London riots of August 2011, and was arrested for using or threatening violence to others near Brentford, West London.
He was charged and remanded in custody at Feltham Young Offenders’ Institution after appearing before magistrates, with the charges against him eventually dropped.
Omar said: "I was just in the wrong place at the wrong time. I got caught up in Brentford and the police grabbed us because we were running. They thought because we were running we must have done something wrong.
"It was scary inside Feltham. I was worried about what would happen if they knew who my brother was. I told him I was innocent and he said he’d stick by me.
"He gave me a little talk when I got put in remand and he said, 'If you actually did do it, just ride your time, get out, and just change your life.' I made sure I kept my head down and listened to my brother’s advice."
He added: "I’m moving forward with my life and I have Mo to thank. My dad said, ‘Why can’t you be more like Mo?’ and that’s what I aim to do now."
Omar was born in 1992, a year after his father, Mukhtar, fled war-torn Somalia with Mo, and met his mother, Fosiya Mohamed, after settling in London.