Ama Sumani, 39, passed away in Accra, Ghana, hours after being told that friends and family had found doctors in the UK and South Africa to treat her.
They had also raised more than £70,000 from donations to pay for drugs which were not available in her home country.
Her friend Janet Simmons said: “She said she was too tired to fight.”
Ms Sumani, a widowed mother-of-two, died at around 1600 GMT on Wednesday in Korle-Bu hospital, in Accra, said Mrs Simmons.
She had been receiving kidney dialysis and treatment there after immigration officials removed Ms Sumani from the University Hospital of Wales in January.
But the drug she needed to prolong her life – thalidomide – is not available in Ghana.
Mrs Simmons, from Cardiff, who returned from spending a month in Ghana on Sunday, said they had just found a doctor in South Africa and another in the UK who would treat terminally-ill Ms Sumani with the drugs.
“We told her this morning but this afternoon she gave up,” she said.
A campaign to allow Ms Sumani to return to the UK for treatment and to raise funds to help her had been backed by people across the UK.
“The British people kept her alive all this time and we would like to thank them for their donations,” said Mrs Simmons.
How much more of this are we supposed to take? Michael Moore’s Sicko covers similar ground but with different targets. We’re supposed to live in a country that stands for universal healthcare, which is a central plank of a civilised society! These people deserve to be massacred at the polls.