Sean was in sixth class in primary school when he started to mitch. He was in a new school at the time, after his family had moved.
"He kept going on the mitch and then he started nicking from the school. He nicked a bike, all that sort of stuff," says his mother, Teresa.
The school expelled him and, because of that, she says, no other school would take him. "He started to fall into the wrong company. He was not coming home and he stole money from me."
She had a meeting with a social worker and asked for counselling for him but nothing happened. Her marriage had broken up and she had a barring order against her husband, who had abused Sean and his older brother Damian. She believed this to be connected with Sean's behaviour and she is convinced that he could have made a better life for himself if he had got counselling.
Desperate to get him back to school, she called the school attendance officers and asked them to summon her. The court sent him to St Michael's assessment centre in Finglas. The assessment took three weeks, but because of the shortage of services, he returned home.
"He just kept falling deeper and deeper, getting involved with the police," Teresa says.
A number of incidents brought him back to court and the judge sent him to St Laurence's special school in Finglas. When his year there was up, she pleaded with them for an extension and they kept him for another six months. After that it was back home and "he started falling back into trouble again".
He was 13 years of age when he found himself in court again. The judge sent him to a consultant who diagnosed him as suffering from a hyperkinetic disorder - the major implication of that was that he could not cope with a normal classroom and needed one-to-one teaching. Nothing of the kind was available for him and the district court judge referred the case to the High Court.
Teresa remembers it took two years to get through the High Court. She estimated at one stage the State had spent £30,000 on fees for him alone. It angers her that she could not get the State to pay £15,000 a year for him to go to an institution in Britain while it was prepared to spend the same amount on court fees. Ultimately a plan was produced by the State for extra facilities at Oberstown in north Co Dublin. She is still waiting for the extra facilities to appear.
Last year, Sean got into trouble again and was sent to St Patrick's for a short period.
His older brother, Damien (19), is in St Patrick's Institution for young offenders for stealing cars. She feels optimistic about Damien's future. "He knows why he's in there and he's getting the counselling and he's done a lot of apprenticeships in the training unit - he's done bricklaying, plastering, all that kind of stuff."
She will not visit him there, nor did she visit Sean while he was there. "One thing I don't do is go to the jail. I wasn't brought up going to a jail and I'm not going to start doing it for my own kids. So that's the bottom line. If you're in there you're in there for a reason."
But Damien telephones her and she keeps in touch with the probation officer there. As for Sean, she does not allow him to live at home because he steals from her. "At the present time Sean is going through the after-hours system through the health board." What that means is that he and other youngsters go to a Garda station and wait for a social worker. "There's normally three to five emergency beds available for one night. The younger ones would get priority. If all the beds are gone they put them out of the police station. The odd time there'd be a nice sergeant and they'd throw them into the cell." Otherwise, it's a matter of finding a doorway for the night, preferably with someone of his own age for protection. But won't he get help when the promised unit opens at Oberstown? "By the time that is done," she says, "Sean will be in Mountjoy."