A Nauru opposition MP Sprent Dabwido, who is recovering in hospital after a heart attack, is due in court for a bail hearing on Friday.
Relatives of Mr Dabwido say he is due to have more tests on Friday morning after being taken to hospital yesterday.
Mr Dabwido, who is diabetic, has spent nearly a month in custody sharing a cell with a fellow suspended opposition MP Squire Jeremiah.
They are facing criminal charges following protests outside parliament.
Mr Dabwido's cousin Marelda Dabwido says it's not clear whether he will be in court for the hearing.
"They did some tests and they are going to repeat them again - that's blood tests and an electrocardiogram. I've seen him and he looks okay."
Marelda Dabwido says her cousin says it's been a mental challenge being in custody for the past few weeks.