Nigel Mabvuure, 20, of Queen's Road, Uppingham, arrived from Zimbabwe with his sister Mercy in August, 2004, to join his mother Fenny.
She had come to Britain as a student two years before and married Uppingham taxi operator Ashley Richardson in August, 2005.
Nigel enrolled at The Rutland College in Oakham and achieved three A-levels at grade A in 2006. After a gap year he went to medical school where he has excelled.
But the Home Office has refused to grant him settlement rights in the UK so he is facing the prospect of returning to the poverty and political unrest of Zimbabwe.
Nigel said: "My case is now at tribunal and I fear that decisions can be made forcing me to leave university and go back to a life of destitution in Zimbabwe. I am terribly upset and depressed about the whole situation."
Mrs Richardson gave up her teaching job in Zimbabwe in 2002 and left behind her children to move to England so she could earn enough money to pay for a good education for them both.
She worked in a series of jobs, including care worker and taxi driver, to send money home so Nigel and Mercy could attend boarding school in Zimbabwe. The siblings spent the holidays with an uncle before joining their mum in England in 2004.
Mrs Richardson said Nigel's right to stay derived from her marriage to Mr Richardson.
She said: "The authorities seem to say that Nigel is no relation to Ashley and they want us to prove we are married.
"I think they are just trying to find a way of kicking him out."
She added: "He wants to work hard because his family is here, not in Zimbabwe. If he was sent back he would be destitute."
Mike Tillbrook, deputy head of campus at The Rutland College, said Nigel had been an outstanding student.
"He worked extremely hard and was very popular with other students," he said.
Nigel is nearing the end of the first year of his course at the Brighton and Sussex Medical School. His course tutor Dr Harry Witchell said: "He is definitely in the top half of the class, in a group where he is among the best of the best.
"He is very well liked and very popular among both staff and students. I would be very disappointed if the decision of the tribunal compromised his ability to finish his course."
Rutland MP Alan Duncan is also supporting Nigel's wish to remain.
He said: "It seems utterly unjust to deprive him of a university education when he seems so bright, able and hard-working. They should reconsider his case."
The tribunal will take place on May 23 in Birmingham.
Mercy is now 18 and is a student at The Rutland College. Because she still lives with her mother and is dependent on her, her residency in the UK is not under threat.