DWIGHT D Eisenhower said, there's no tragedy in life like the death of a child. Things never get back to the way they were.
Tony and Mary Heffernan suffered this almost unimaginable torment twice.
On January 18, 2011, their five-year-old daughter Saoirse died of an extremely rare, and incurable, neuro-degenerative condition called Battens disease.
Last Sunday, just after dawn in Co Kerry, Saoirse's brother Liam, only five himself, succumbed finally to the same disease. He was released from his distress, his pain. Perhaps he could take no more pain. No child in the world should go through what Liam went through.
The night before Liam's big sister died, Mary told Saoirse a remarkable story. She said to Saoirse that she will be an angel in heaven but that she was lucky enough to go early – and that mummy and daddy and Liam would follow her to heaven soon.
Last January, I was privileged to spend the morning at home in Castlemaine, Co Kerry, with Liam and his mother and father. He was blind and partially deaf, on his mother's lap staring at the telly with his favourite dinosaur cartoons on it, kicking his little legs and waving his arms about.
He couldn't speak. He was obviously in some form of distress. His attention was still vaguely focused on the cartoons in front of him.
Mary and Tony flooded their son with love. He didn't have long to live. It was heartbreaking. But Mary and Tony never gave up.
"In a few more months, there is going to be nothing," Mary said. "It's not something I like to think about too much."
"You can't help it though," Tony said. "We have to concentrate on now, to keep as positive as we can.
"It is very hard to pick up a white coffin," Tony added. "It is harder to put it down. In the next couple of months we're probably going to have to lift Liam's coffin and put a coffin down for the second time."
Three months on from that heartrending day in Co Kerry,
Tony and Mary put a white coffin into the ground for the second time. Last Tuesday at St Gobnait's Church in Keel, next door to their house on the Dingle Peninsula, Liam was laid to rest beside his sister.
Liam's parents are two good and decent people with a selfless view of human life. Nietzsche said that if a human being put his ear to the heart chamber of the world and heard the "innumerable shouts of woe, the roar which lies on the other side of silence", he would break into pieces. Tony and Mary Heffernan haven't broken into pieces despite all their suffering and pain. They continue to give all their time to their charity, Bee For Battens, to help children who suffer like their kids suffered.
"We've learned with the charity that there are other people burying kids with different conditions other than Battens," Mary told me that sad January day in Kerry – with Liam on her lap.
"One of the things that our bereavement support at the charity does is keep them busy. They get a call frequently to see that they are alright. I'm hoping they'll do the same for us, to get us through, because we'll need help."
"I don't know how we'll be after that," Tony added. "I hope we'll have some kind of a life. But the charity will go on and make a difference for sick kids that we couldn't do for our kids."
The agony and heartbreak Tony and Mary have endured are almost unthinkable for anyone, let alone any parent. Yet you could draw some sort of inspiration from them.
"Saoirse died here in this room," Tony said that day in the house, with Liam downstairs, "cuddled by me and mum. In the end, we said our goodbyes and lost the fight with her. I like to think she beat Battens disease because her body relaxed and all the facial contortions and body shapes . . . all her muscles which were in spasm for a year, all just fully relaxed and you could see Saoirse's face just relax back to . . . just a loving face, really."
We all would like to think that little Liam, even in death, beat Battens disease too.
The words of Liam's proud mother Mary in her address at the church last Tuesday said it all, with a tragic beauty. Her words – reproduced here, to the right, with Mary and Tony's kind permission – echoed all the way to her kids in heaven.
Donations can be made to the Saoirse Foundation, AIB Tralee, Co Kerry, account number 85130187; sort code 93-62-19; IE13AIBK93621985130187; swift code AIBKIE2D
Postal donations can be made to Bee For Battens, the Saoirse Foundation, Castledrum, Castlemaine, Co Kerry
You can also donate by sending old mobile phones free of charge to the Bee For Battens Appeal, Freepost, PO BOX 7958, Dublin 11
More details available on www.beeforbattens.org