The boy has now been discharged from the hospital, Elin Widfeldt, press communicator at Sahlgrenska Hospital, told the newspaper.
It was late Tuesday night last week that a woman and a child died when a pleasure boat collided with a merchant ship. Four people - a man, a woman and two young children - were on board.
The man and a child were rescued by private individuals who had anchored nearby for the night.
Both were taken to hospital, and the man was discharged on Monday.
Two people, the merchant ship's commander and the Swedish Maritime Administration's pilot who was also on board, are suspected of causing death and negligence in traffic.
Both deny any wrongdoing.
