Australian tennis coach Nick Philippoussis has suffered a massive stroke in a US jail and will likely never face trial for charges he sexual assaulted two young girls he trained in California.

A San Diego judge was told on Thursday 68-year-old Philippoussis, the father of former world top 10 Australian player Mark Philippoussis, is catatonic after the stroke and has been held under guard and handcuffed to a bed in a public hospital for several months.

Philippoussis Sr faced a maximum life in prison sentence if convicted of 14 charges relating to sexual assault of children under 10-years-old and lewd acts upon a child.

The criminal case is now on hold pending Philippoussis Sr's health.

"He is conscious, but is not responding to any stimuli," Philippoussis Sr's lawyer Ryan Tegnelia said.

"The best way to describe his state would be catatonic."

The two alleged victims were nine years old and Philippoussis Sr allegedly assaulted them for almost a year in different locations including his car, home and a tennis complex.

Philippoussis Sr had been held at San Diego County Jail since his shock arrest during a morning raid on his San Diego home in July.

He suffered the stroke in November at the jail, was transported to a public hospital and has been handcuffed to a bed and guarded by sheriff deputies.

Mr Tegnelia rejected speculation Philippoussis could be faking illness to avoid a trial and jail.

"No-one has accused him of trying to pull a fast one," Mr Tegnelia said.

Philippoussis Sr has been kept in jail on $US9.2 million bail, but Mr Tegnelia, with the support of prosecutors, successfully asked for the bail to be lifted and he be held on his own recognisance.

This would halt the need for guards and handcuffs and allow his son and other family members to visit with less restrictions.

He will remain in hospital and his passport has been handed over to prosecutors.

Deputy district attorney Garret Wong said he had consulted the physicians caring for Philippoussis Sr and was told "his prognosis was poor".

"We felt he did not pose a threat to the public's safety," Mr Wong said.

The victims and their families were also briefed on Philippoussis Sr's condition and told he was not a threat.

A court hearing was scheduled for June to evaluate Philippoussis Sr's condition.

"We have been informed recovery is not very likely," Mr Tegnelia said.