Fahim, who slipped into a coma on September 10 after falling into an uncovered manhole in the Fish Market area of Doha, was formally declared "dead" at midnight on Monday.
The boy was declared "brain-dead" at the paediatric intensive care unit of the Hamad General Hospital.
Fahim had come to Doha along with his mother and an 18-month-old sister on a visit in April, to meet his father, Mohamed Sirajuddin, an accountant with a private firm.
The family hails from Parankipatanam in Tamil Nadu's Cudallore district, close to the Puducherry border, Gulf Times reported.