Gary McKinnon, the man accused by US prosecutors of "the biggest military hack of all time", has suffered a severe deterioration in his mental health, according to his mother.
McKinnon, who has been diagnosed with Asperger's syndrome, was not faring well following a serious setback in court in July.
"He had a breakdown after the last court case," Sharp told ZDNet UK at a protest outside the US embassy on Thursday. "He can't look himself in the eye in the mirror."
Wilson Sharp, McKinnon's stepfather, said that the decision by two high court judges had deeply affected the self-confessed hacker.
"[Gary] took it really badly," said Wilson Sharp. "He switched off his phones and the TV, wouldn't speak to anyone, and was shouting at people. Most uncharacteristic. We were worried in case he did something stupid."
Sharp said that the family had contacted autism expert professor Simon Baron Cohen, who had agreed to meet McKinnon, along with Jeremy Turk, an expert in autism and depression. The three met at McKinnon's barristers' chambers, where Turk had said that McKinnon was in the process of "detaching from himself", according to Sharp.
The protest outside the US embassy on Thursday, which was organised by civil liberties group Liberty, was designed to draw attention to the extradition treaty the UK has with the US. The American Civil Liberties Union also sent a letter to foreign secretary David Miliband requesting that extradition arrangements be scrutinised.
Shami Chakrabarti, director of Liberty said:
"The intervention of Liberty's sister, the American Civil Liberties Union, proves that Britain's Extradition Act is an international embarrassment. Vulnerable people like Gary McKinnon can be bundled off to other countries when they ought to be dealt with at home. Janis Sharp's campaign for fairness for her son Gary has touched the hearts of parents everywhere. If Parliament doesn't amend Britain's rotten Extradition Act to put discretion and common sense back into the system, other vulnerable sons and daughters are bound to suffer."
Chakrabarti and Sharp outside the US Embassy on Thursday