A father-of-two died of sepsis on Mother’s Day after noticing a spot on his leg a few days earlier.
Brett Dymond, 38, from Hillingdon, west London, had his life support switched off on 19 March after suffering three cardiac arrests and brain damage in ICU.
His wife Charlene had called non-emergency number 111 when he struggled to walk, felt weak and had hallucinations, family friend Kelly Sims said.
She added before this he felt "like he was coming down with something” and a spot appeared on his leg “which spread with swelling”.
Dymond, who has two sons Tommy, two, and Reiss, 16, had gone to work despite feeling ill but was forced to come home early, Sims added.
She said he was advised to go to the hospital to be checked and was admitted for sepsis before succumbing to the illness on Mother’s Day.
Dymond's sepsis was later verified as being caused by necrotising fasciitis (flesh-eating bug) and haemolytic strep A, which infected his blood and caused multi-organ failure.
He had been put into an induced coma and on kidney dialysis to help save him, with a doctor describing him as “the sickest patient they'd seen in ICU in the last five years”.
Sims, who set up a GofundMe for the family, wrote: “Charlene, Tommy and Reiss have just lost their entire world on Mother's day!”
She added: “This was the devastating news that we all feared, that it was the end of the road for Brett, a selfless young man with a pure heart, and a wife and children who needed him.
“We lost our Son, Father, Husband, Brother, uncle, Cousin and friend on Mother's day!
“With all of this in mind we would like to raise as much money as possible towards the cost of his funeral, as being so young, there was no plan or insurance in place.
“This will hopefully take away some of the financial pressures they will now be facing to help make sure the next chapter is the happiest it can be, under the circumstances.”
Sepsis is a life-threatening condition which arises when the body’s response to infection injures its own tissues and organs.
Symptoms can include shock, fever or increased breathing and confusion.