A young married couple have died within hours of each other after the husband mysteriously collapsed and passed away before his cancer-stricken wife succumbed to her disease.

Neil Carruthers, 34, was caring for his wife, Tina Nedelcu Carruthers, 29, who was suffering from a brain tumor, when he collapsed as he left her bedroom in Stoneham, Massachusetts on August 11.

His mother Rosanne, a nurse, desperately tried to revive him but neither she nor emergency responders could save him and he died in Winchester Hospital.

The sudden death of the active man has left relatives and doctors baffled. He had attended a physical with a doctor just days prior and nothing seemed amiss.

An autopsy is being carried out on his body to determine his cause of death.

That night, his mother broke the news to Tina - who had lost her ability to speak - and she appeared to understand, Rosanne told the Boston Globe.

'When I came home, I went in and I held her hand and I told her, "Tina, he didn't make it, he's going to have to be there waiting for you," and tears ran right down her cheeks,' Rosanne said.

Just 46 hours later, Tina passed away while in hospice care.

Tina, who grew up in Romania before moving to the U.S. aged seven, was first diagnosed with a brain tumor after she began suffering seizures out of high school.

She underwent surgery in 2006 which left her temporarily paralyzed and she had to learn how to talk and walk again.

But after the operation, she was deemed cancer free - and soon after, she met Neil on a Christian Adventist dating website, where they bonded over their faith.

The couple married on September 5, 2010 in Lawrenceville, Georgia - near to Tina's home - and even though he knew his wife's illness might return, he remained devoted to her and her care.

'He told me, "Mom, whatever time we have I want to spend with her",' Rosanne told the Globe.

Nine months after their wedding, the cancer did indeed return and this time it could not be beaten.

But 'he never, never gave up,' his mother said. 'When she lost her speech, I would have been so frustrated. He'd say, "Mom, she can tell me so much with her eyes... She can tell me more than most people can tell me with words".'

The couple moved in with Neil's parents in Stoneham and he gave up his job at Winchester Hospital so that he could care for her full time. He enjoyed reading her Bible passages, his mother said.

'I know he was helping to prepare her,' Rosanne said. 'But for me as a mother, as a Christian, it was as if she was preparing him as well.'

The couple will be remembered at a joint funeral in Stoneham on Saturday.

'God knew they were going to go at the same time,' Rosanne said.