In a GoFundMe set up to bring his body home, Craig Mackintosh’s sister Lorna revealed that he had been killed in Ukraine on August 24.
She said that her brother, from Thetford, Norfolk, had lost his life “in the line of duty”.
“Please help us bring this war hero home,” Ms Mackintosh wrote.
“Our brother bravely volunteered to go to (Ukraine) as a medic to help save lives in this war torn country.
“In the line of duty, helping others he lost his life. This selfless man is currently stranded in a morgue in Ukraine and there is no help to get him home.”
She said it would cost around £4,000 to bring his body back to the UK.
“We have spoken to an international funeral provider and it’s going to cost around £4,000 to have him repatriated back to the UK.
“He gave his life to save others and he needs to come back home to have the service he deserves. A true hero’s service surrounded by his family and friends. Please, please help to bring our hero home.”
As of Wednesday evening, the GoFundMe had exceeded its target, raising £4,590.
An FCDO Spokesperson told the PA news agency: “We are supporting the family of a British man who has died in Ukraine and are in contact with the local authorities.”