The lawsuit seeks more than $50,000 from David Hatyina and Renee Melbourn of Bartlett, claiming the family of Tony Borcia suffered emotional distress from the youngster's death last July.
Police say the Libertyville boy was run over by a boat operated by Hatyina.
The lawsuit says Melbourn assisted with the financial care and maintenance of the boat.
No comment so far from lawyers for Melbourn and Hatyina.