A 27-year-old Irish man is to face trial in Greece on charges of people smuggling, membership of a criminal organisation and espionage.
Seán Binder, who is from Castlegregory in Co Kerry, is one of 24 people charged in connection with assisting refugees and migrants.
He denies all charges.
He was arrested in 2018 on the Greek island of Lesbos while volunteering to assist refugees.
He spent more than 100 days in a Greek jail before being granted bail. He returned to Greece this week to face trial.
His mother, Fanny, told Newstalk Breakfast her son helped people arriving in Greece with blankets and medical care.
"He coordinated search and rescue - most people think he was out at sea, but it was actually more like spotting.
"They were at the beaches and helped people off the boats when they were landing - giving them blankets, a bottle of water.
"Sometimes they needed medical care and so he would assist [in] that and coordinate these shifts.
"They also had a medical unit in Moria in the camp, where they supplied medical care basically".
She says her son faces up to 20 years in prison on these charges.
"The charges he faces are up to 25 years - although I heard yesterday that the law has changed, and I think the maximum is 20 years - which doesn't make [it] any better, really.
"So every felony charge he has would have a maximum of 20 years, but they can't be put in jail longer for 20 years.
"That's what he's facing today: the start of the trial, they only try the misdemeanors but they still carry a possible seven years [sentence]."
'Criminalising young people'
Fanny says she believes this case is being used to scare off other humanitarian workers.
"It is very hard to understand because, especially in Ireland, there is rescue missions coming from Government.
"They are celebrated as heroes, and Seán and his colleagues are civilians doing a similar thing and being criminalised for it.
"The idea behind this, I think, is to scare people away from search and rescue missions.
"It's a successful mission, because there is no search and rescue anymore on the island of Lesbos since they were in pre-trial detention.
"So [it's] very much a try to deal with the so-called migrant crisis in a way that's criminalising young people to deter other people from coming".
And Fanny is now in Greece with her son, who she says is scared.
"I arrived yesterday on Lesbos, I'm with him now.
"He's good - he is scared, I would say, because it is hard to know what could come because at this stage everything is open.
"Nobody knows how this will end today or in the future".
Speaking earlier this week, Seán said he was "terrified" at the prospect of a long-term jail sentence - but would do it all again if he had to.
"Facing 25 years in prison, yeah, that’s half my life. That will be half my life spent in prison, that is terrifying", he said.
"I am worried but at the same time, I would still do it again because there is nothing wrong with it.
"I mean, what would you do? If you see someone drowning in the sea? If, like me, would reach an arm out and try to help, then you have committed the same supposed crime that I have committed.
"We should never accept that that could be criminalizable".