"God is great!" he tells AFP as he waits for relatives in the hospital entrance.
He is glad to be alive and on his feet, but the frail man in his 60s carries a deep sadness, having lost his brother and his brother's son to the deadly epidemic sweeping west Africa.
"I was in a lot of pain. I was between life and death. The doctors told me to eat and drink a lot," he said.
"I told myself I was preparing to join my brother in the afterlife. It was the hardest test because I could not receive a single visit from my family."
"Old Diallo" was treated by Doctors Without Borders (known by its French acronym MSF) in the Donka hospital in the capital Conakry.
He won't reveal his identity or let his photo be taken, fearing the stigma that has quickly descended on victims of the deadly haemorrhagic fever.
"It is always bad to be seen as a plague victim."
Of 232 patients admitted to the MSF centre at Donka, more than half -- 124 -- have been confirmed to have Ebola, of which only 64 have survived, according to MSF.
"Old Diallo" said he was contaminated by a woman from Koidu in eastern Sierra Leone, who had come to Conakry for treatment.
He came into contact with her while at the bedside of his brother, who was then suffering from typhoid but would later die of Ebola -- possibly caught from the same woman.
"No one knew what she was suffering from," he said.
There is no cure for the sickness -- which has killed anywhere between 25 and 90 percent of cases in epidemics over the years.
MSF says that if patients receive treatment for the secondary infections and are well-rehydrated in adequate health centres, their chances of survival are higher.
- No hugging -
"Old Diallo" interrupts his story for the arrival of his son Ibrahima, a man in his 30s.
"Dad, is that you?" he asks, hesitantly.
Their reunion is emotional, but without contact. They don't shake hands, let alone hug. They just smile and cry.
"Papa is back among us. We must thank the good Lord who saved my father."
"If there is a God up there, there are also gods on earth: Doctors Without Borders and their colleagues," says Ibrahima.
Having already lost two relatives, the family was preparing to mourn one more of their kin, he says.
They won't drive straight home. "For now, I will take him to be alone somewhere," to shield him from the fear and stigma that his return will inevitably arouse in friends and neighbours.
Ebola survivors often become pariahs, for a variety of reasons: not just the fear of contagion, but also because they are seen as abnormal, or because their survival is a painful reminder for the families of those who were less fortunate.
The epidemic has bred fear and suspicion, particularly in rural areas where many believe that foreigners are responsible for spreading the disease, including the very humanitarian groups trying to combat its spread.
A well-dressed woman in her 20s, approached outside the MSF health centre, confirmed she was another Ebola survivor, but she too refused to give her name.
"Revealing my identity means taking a big risk. I'll be rejected by the population," said the woman, who had returned to visit the doctors who saved her life.
To many, she said, "we are ghosts."