Stuart Hutchison was diagnosed with a brain tumour in 2011, and underwent surgery and bouts of chemotherapy to treat it.
But the cancer spread to his bones and he suffered another aggressive tumour.
Stuart, who married wife Danielle, 22, in January, doted on his two-year-old French bulldog, Nero.
The couple also had another dog, Nala, aged four, and Amelia - the puppy of Nala and Nero.
In a tragic twist of fate, Nero died just 15 minutes after his owner, on August 11.
Heartbroken mum, Fiona Conaghan, 52, said: "Stuart died about 1.15pm that day, and Nero died roughly 15 minutes later.
"He had three dogs, but him and Nero were like one man and his dog.
"Nero was the dog which was always with him.
"Danielle was heartbroken to have lost both of them, but she has been so strong.
"We got Stuart home four weeks ago because he wanted to die at home because that's where he was born.
"We cared for him at home.
"We expected it but it is still tough.
"It is still a shock and traumatic when it finally comes."
Stuart and Danielle, a pharmacy assistant, got together six years ago and got engaged in 2017.
They lived in Alloa, Clackmannanshire, before Stuart spent his final month living with his mum.
Fiona, who was a full-time carer for her son, said: "Danielle had been staying at ours with Stuart and woke up one morning and realised her glasses were broken.
"Her dad said he would go and get another pair from her and Stuart's house to save her leaving him as we knew he didn't have long left.
"When he got there he realised the dog had taken unwell and took him to the emergency vets.
"They said he had ruptured something in his spine but he had been totally fine before that."
Stuart was first diagnosed with cancer in 2011, and relapsed in 2014 and then 2018.
He was never in remission, and his mum said his death was not unexpected.
Fiona added: "He went into hospital to start chemo at the end of 2018 and he was then having scans every three months.
"At a scan in March, they said the chemo was working.
"Him and Danielle went on holiday to Spain in May and he started getting a pain in his hand.
"He went for a check up and they were convinced there was nothing wrong.
"But then by June it started to affect his whole arm and that's when they did a scan and saw the cancer had taken over his whole brain and had spread to his bones and his pelvis.
"We always knew this was a possibility.
"Stuart was a strong, loveable character, everyone loved him."