The boy has now been discharged from the hospital, Elin Widfeldt, press communicator at Sahlgrenska Hospital, tells the newspaper.
It was late Tuesday night when a woman and a child died after 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 were anchored nearby for the night.
Both were taken to hospital and the man was discharged from hospital on Monday.
Two people - the merchant ship's captain and the Swedish Maritime Administration pilot who was also on board - are suspected of causing death and negligence in traffic.
Both deny any wrongdoing.
