David Lynch, the brother-in-law of Limerick man Jason Corbett who died in the US last week, has said he and three of Mr Corbett's siblings are staying in North Carolina to fight a legal battle and get custody of his two children.
Ten-year-old Jack and Sarah, aged eight, have been placed in the custody of their stepmother.
Speaking on RTÉ's Morning Ireland, Mr Lynch said they had been in contact with US child protection services before travelling to North Carolina and were told the children would be put in their care as soon as they arrived.
However, he said when they arrived in the US they were told the children had been placed in the care of their stepmother and that they had no rights.
Mr Lynch said they have had little contact with the children since then.
He added: "It is all attorneys now as papers had been lodged in court before we arrived.
"We have a custody hearing this Friday...These children are two Irish citizens, their father was an Irish citizen. They are solely Irish citizens.
"They were linked to Jason's work visa - they are technically illegal in the US now."
Mr Lynch also said trying to ensure his brother-in-law was not buried in the US was another issue they had to contend with.
"It is a nightmare. One of my best friends died and the first thing I had to do was to jump on a plane and engage in attorneys and stop funeral arrangements in America and secure his body."
He said his brother-in-law had told him his wishes and that if anything happened to him he wanted to be buried in Ireland with his first wife Mags, who died from an asthma attack in 2006 aged 31.
Mr Corbett, 39, moved to the US four years ago with his children and his second wife.
His body has been released to the Corbett family, but Mr Lynch said: "His body will be brought home as soon as a flight can be arranged but we have to stay and fight the legal battle.
"We won't bury him until his two children are there."
The children's grandmother, Marian Fitzpatrick, said she hopes to get them back to Ireland as soon as possible.
"I only just spoke to my grandkids once since this happened, I just told them I love them, but I was only allowed to speak to them for a few seconds," Ms Fitzpatrick said.
"We are all just in bits and my husband Michael is very upset and my other sons and daughters, especially my daughter Catherine who is very close to them and who lived with Jason and the kids for six months to help him after Mags died," she added.
"We are getting in contact with everybody we can to help us to get them two children home. That is all we want. "
The Department of Foreign Affairs has offered consular assistance to the family.
However, Mr Lynch said they had not had much help so far.
"We had contact with a consular on Wednesday and I rang the consul to give them an update yesterday, but we have had no help from the consulate."
Mr Corbett, who was originally from the Janesboro area of Limerick city, was found with head injuries at his home in the early hours of Sunday 2 August.
The County Sheriff's office received a call at around 3am local time regarding a domestic disturbance and officers found Mr Corbett unconscious. He was treated at the scene but pronounced dead a short time later.
In a statement, the Davidson County Sheriff's Office said no arrests were made at the time and the investigation is continuing but no one from "outside the home is being sought in this case".