The three brothers then washed their hands as they had forgotten to when they go on the boat.
Mano then told his mother he was having an asthma attack and took a puff on the inhaler. His condition kept deteriorating so took two more puffs on the inhaler.
His mother quickly threw flowers he had picked for her earlier that day overboard thinking it may have been the cause of the attack.
Deschamps told police it was the worst attack she had seen her son have.
"I had never seen him like this. He was sitting and gasping for breath. Each time he had tried to breathe in his body contracted and his shoulder raised."
The family then called for help on the maritime radio and a doctor holidaying on St Omer Bay heard the call and set out on his inflatable boat to help the tourists.
But by now Mano's lips were blue and his eyes were wide. Mano's father and Maxime rowed to shore in their dinghy to find help.
When they got to shore Maxime ran to a house with lights on for help and a couple welcomed them in at about 8.15pm.
His mother arrived with ventolin and performed CPR on her limp son as he lay on the deck of the house while they waited for a rescue helicopter to arrive.
Dr Nigel Gilchrist arrived first and found Mano was not breathing.
The rescue helicopter arrived, but at 9.15pm Mano was declared dead at the scene.
Not long afterwards, Maxime who had been looking after their younger brother inside the St Omer Rd house started throwing up bile, foam and well-digested food. He was sweating and crying in pain and given oxygen by the medics. He fully recovered after being given his asthma medication.
In her findings released today, Coroner Carla na Nagara said the post-mortem examination found Mano had died form an anaphylactic shock caused by an unknown allergen. Asthma also contributed to his death.
The rhum arrange flavouring contained cardamom seeds and while it was not specifically tested for during the post-mortem, pathologist Dr Elizabeth Roberts said it was a known allergen for some. Other foods or wasp stings could also trigger similar reactions.