Delaney further revealed that his son went through a surgery to remove the tumor early previous year and continued with treatments as well. The cancer returned in the autumn.
He had undergone surgery to remove the tumour early previous year, but the cancer then returned and he passed away in January.
"Henry was a joy", wrote Delaney. He was savvy, clever, and naughty and we had such a significant number of great experiences together, especially after he'd moved home after fifteen months living in doctor's facilities.
Though left with "significant physical disabilities", Henry learned sign language and shuffled from place to place "on his handsome little bum".
Fellow comedians such as Andy Richter, Patton Oswalt and Mindy Kaling share their condolences for Delaney. "Sending love to you and your family". Love and love and love to you and your family'.
Delaney signed off his moving message by thanking the doctors who fought to save Henry's life and asked fans to donate to the Rainbow Trust and Noah's Ark, two charities that specialise in providing care to sick children.
Probably busy watching puppy videos on Instagram.
He also urged Britons to support the NHS in any way possible.
He also added that numerous cab drivers in London would donate to GOSH's trust to help Henry and other kids like him. Wrote the actor, "I am astonished by the love-in-action displayed by Henry's mom and his brothers".
'I don't want to miss out on their handsome lives.
I have very sad news. They are the reason I will attempt to not run frantic with distress. "I'm voracious for more encounters with them".
'Thank you, handsome Henry, for spending as much time with us as you did. I am desperately sad right now, but I can say with authority that there is good in this world'.
Rob, who has two other children with his wife, broke the news on his official Facebook page last night that Henry died last month. Much obliged to you, wonderful Henry, for investing as much energy with us as you did.
While American, Delaney has mainly found success in the United Kingdom, in large part due to the hit TV series Catastrophe, the show he co-created alongside fellow co-star Sharon Horgan.