Anton Green was living in Bogota at the time
Family photo Anton Green smiles and looks at the camera.
Footballer Marcus Rashford has joined an appeal to help find the brother of a former teammate after he went missing in Colombia more than six weeks ago.
Anton Green, brother of ex-Manchester United youth team defender Ro-shaun Williams, has not been heard from since 6 August.
Rashford described Whalley Range 43-year-old Green as a "family friend" on his social media as he posted an appeal for information.
Green's sister Sian Tuohey said the family had not been given much information about the progress of any efforts to find him by the Colombian authorities.
The Foreign, Commonwealth and Development Office said it was in touch with local authorities in the South American country.
Siblings Ro-shaun and Sian are appealing for information to find Anton
Family photo Brother Roshaun, Anton and sister Sian, along with Sian's daughter all have bright smiles as they sit down.
Tuohey said her brother, whom she described as a "happy, decent guy", had been living in Colombia for three years, settling there while travelling.
She said he spoke Spanish fluently and had recently moved to Fontibon in the capital, Bogota.
She said: "We're in a difficult position where we're all the way in a different continent, there's nothing we can do.
"And the help just isn't enough."
Family and friends last heard from Anton Green on 6 August
Family photo A photgraph of a man. He is black, in his 30s, and is smiling for the camera.
She said "nothing had seemed unusual" in the family's last contacts with him.
But she said his phone had been off since 8 August, and there has been no response to emails from his family, and no activity on his social media accounts.
Anton's friends in Colombia were also reported not to have seen or heard from him.
The only contact the family has had from Colombian authorities was confirmation that a missing person case had been opened, she said.
"It is not a good enough process for families to go weeks and weeks without engagement," she said.
"Because we're not being given any updates the the anxiety and stress is really building.
"My mum is feeling very unwell, I can see she isn't coping with it," she added.
Rashford made an appeal on his Instagram page
Instagram Marcus Rashford's Instagram page shows a post appealing for information about missing Anton Green.
A spokesperson for the Foreign Commonwealth Development Office said: "We are supporting the family of a British man reported missing in Colombia and are in touch with local authorities."
Rashford posted on his Instagram account appealing for "anyone who has any information to please get in touch".