An al-Jazeera journalist jailed without trial in Egypt since last August is to be released from jail on health grounds, nearly a year after he was arrested while covering the violent dispersal of a protest camp in Cairo, prosecutors said on Monday.

Abdullah Elshamy, a reporter for al-Jazeera Arabic, has been in jail for 306 days accused of several violence-related crimes, and is expected to be released on Tuesday morning, his brother said.

Elshamy spent nearly half his jail-time on hunger-strike in protest at his politicised case, and his family said he had lost over a third of body weight. Elshamy's plight sparked global outcry, as his case came to symbolise the extent of a crackdown on dissent that has now seen 16 journalists jailed among at least 16,000 political detainees.

After doctors warned Elshamy was at risk of death, authorities sent him to solitary confinement and refused to admit the severity of his condition – until Monday afternoon, when he and 10 others from his case were ordered released for health reasons.

Elshamy's younger brother Mosa'ab, an award-winning independent photojournalist, said on Monday night that the move marked a "huge victory" for the reporter, whom the authorities had denied was undergoing a hunger-strike.

"This is a huge victory for Abdullah," said Mosa'ab. "The fact he gets released on a health basis means his hunger strike, which he took till the very end, has got what he achieved. It's a big victory for him, and this is the prosecutors recognising his hunger strike and his struggle."

But Mosa'ab Elshamy warned that Abdullah's case – which his supporters say is clearly politicised, and which has never been brought to trial – has still not been dropped. "It doesn't end the case – technically if they refer the case to trial, he will have to go to court," said the younger Elshamy.

In a separate case, three of Elshamy's colleagues from Al Jazeera English – jailed since late December – will discover their fate within a week, a judge announced on Monday. Canadian-Egyptian producer Mohamed Fahmy, Australian reporter Peter Greste, and local producer Baher Mohamed are accused of helping terrorists and smearing Egypt's reputation. Following a three-month trial, a verdict will be announced on 23 June.