Catastrophe star Rob Delaney published an emotional essay on the pain of watching his late son battle cancer, in the hopes that his words would help other parents of sick children.

Delaney, 41, lost his two-year-old Henry in January, but had written the essay the year before as part of a book proposal that he shelved once Henry’s disease became terminal.

The essay, published Sept 17 on Medium website, began with a visit to see Henry in the hospital, and how Delaney avoided travelling on buses with him because the toddler’s medical devices drew stares.

“I don’t want to have to jostle with other curious passengers when I have to turn on his suction machine to suck out the saliva and mucus that collects in his tracheotomy tube,” Delaney wrote.

The comedian then explained just how he and his wife Leah discovered their son’s illness, which started with him vomiting at his older brother’s birthday party.

“I’d been feeding him blueberries so there were maybe 15 or 20 recognisable blueberries in there. Did I feed him too many? Had I done something wrong?” Delaney wrote.

But Henry’s vomiting continued, and soon, there was cause for concern. Delaney visited several different doctors, and despite some suggested issues like a UTI, Henry’s health continued to decline and his vomiting continued, unrelenting.

“My baby was getting smaller, and that is a (expletive)up thing to see,” Delaney wrote. “I would try not to cry in front of his older brothers and fail and they’d ask why, and I would say it was because I was scared.”

Eventually, an MRI revealed Henry had an ependymoma tumour on his posterior fossa, wrapped around important cranial nerves. It was removed, but in doing so, the nerves were damaged, leaving him with Bell’s palsy, a lazy left eye and hearing loss.

Henry also had a tracheotomy tube that rendered him mute – something Delaney struggled with greatly.

“Henry’s tracheotomy tube prevents him from speaking, so I haven’t heard him make a peep for over a year. My wife recently walked in on me crying and listening to recordings of him babbling, from before his diagnosis and surgery,” Delaney wrote.

“I’d recorded his brothers doing Alan Partridge impressions and Henry was in the background, probably playing with the dishwasher, and just talking to himself, in fluent baby. Oh my God I want to hear him again.”

Delaney’s essay ended abruptly, and he added a passage at the end explaining that he’d pushed it to the side once Henry’s tumour returned.

“I stopped writing when we saw the new, bad MRI. My wife and his brothers and I just wanted to be with him around the clock and make sure his final months were happy. And they were,” he wrote.

The actor said he published the essay months later because he wanted it to reach the parents of other sick children, which had been his intended audience in the first place.

“They were always so tired and sad, like ghosts, walking the halls of the hospitals, and I wanted them to know someone understood and cared,” he wrote.

“I’d still like them to know that these few pages are, for them. Or for you.”

Delaney wrote on Twitter on Sept 22 that he’d received greatly positive reactions to the essay, and was happy to have shared it.

He and his wife announced in July they were expecting their fourth child. – New York Daily News/Tribune News Service