Businessman Radovan Krejcir is genuinely sick, his doctor told a Sunday newspaper.
Marian Tupy had previously admitted falsifying insurance documents so that Krejcir could receive a R4.5 million payout for bladder cancer.
But Tupy told this week's edition of the Sunday Times the bladder cancer diagnosis was genuine.
He denied swapping a biopsy sample from another patient with Krejcir's - which he had previously admitted to.
Fraud charges against Krejcir for the bladder cancer claim were provisionally withdrawn in the Johannesburg Magistrate's Court in April.
The State withdrew the charges, citing other High Court cases underway which overlapped with the case.
Earlier this month, an armed robbery case involving Krejcir and two co-accused was postponed in the Pretoria Magistrate's Court.
The trio faced charges of robbing a Pretoria West electronics shop owned by a Pakistani national.
They were granted bail in February.
During his bail application Krejcir claimed his arrest was “retribution” for legal action he instituted against Police Minister Nathi Mthethwa following a police raid on his home in Bedfordview, Johannesburg, in March 2011.
Krejcir is also embroiled in a legal battle to fend off attempts by the Czech government to extradite him, and has applied for refugee status in South Africa. - Sapa