Actress Leigh Arnold said her family was left heartbroken when her brother Nicky (34) was found dead at their family home in Foxrock last October.
The cause of death is still unknown, but it is believed the businessman may have died from an aneurysm.
The actress penned a heartfelt tribute on her website yesterday, where she thanked her followers for their "incredibly moving, supportive and breathtakingly kind messages regarding the passing away of my darling little brother Nicky.
"As you can imagine, our hearts are broken and we needed to huddle together as a family and mourn him quietly and privately," she said.
"Having our kiddies has given my parents, brother, sister and I a sense of hope and strength and we know Nicky loved them all to the moon and back again."
The 36-year-old said the tragedy has pushed her to re-evaluate her life.
"It made me put my life in perspective, and we decided as a family to take a step back and re-evaluate our lives and what our hopes and dreams are, not only for ourselves but for our children," she said.
"Unfortunately, sometimes a tragedy is the thing that gives people the relevant a**e kicking they need in order to realise we only have one life.
"God forbid if anything ever were to happen, [I want to know] we lived it to the full and without negativity and regret.
Leigh is married to director Steve Davies and the couple have two children together, Hunter (three) and Piper, who is almost four months old.
Their two-week-old son, Flynn, tragically died of cot death in 2013.
The couple have decided to take an extended break from Dublin and have relocated to their holiday home in Spain for the coming months.
"Right now, as I sit here and feel the warm breeze on my back as the sun fills the sky, I am so aware of all the magic that surrounds us, which we so often take for granted," she said.
"The food on our plates, our warm bed, the wine in our glasses, the friends and family we have and above all, the life we lead.
"Happy New Year everyone. Please don't allow yourself any regrets," she added.
Before Nicky's death, Leigh, who is known for her TV roles in The Clinic and Deception, said she was hoping to start a career as a screenwriter.
"I've written plays and screenplays," she told the Herald.
"Putting yourself out there for people who don't know you and don't love you unconditionally like your family is really daunting, so I never really did that, but I do intend on that being the next chapter of my life."
However, she said she hasn't put her acting days behind her.
"I'm always an actress and that's what I adore, but when you have small babies it's very difficult to be on set," she said.
"There's no point in putting yourself forward for stuff when it doesn't make sense for you, and it didn't for me for the past couple of years."