A "missing" flyer was taped to the lochs near the TD Garden after Michael Kelleher disappeared in 2017. —Jessica Rinaldi/Globe Staff

BOSTON (AP) — The mother of a Southborough man who drowned in the Charles River after drinking alcohol at a Boston Celtics game is suing TD Garden and its parent company for unspecified damages.

Lori Kelleher filed a wrongful death lawsuit Wednesday alleging that TD Garden staff continued to serve Michael Kelleher, ignored his “vulnerable, impaired condition and failed to protect him,” The Boston Globe reported.

Kelleher was last seen March 29, 2017, leaving a Boston Celtics game and was pulled from the Charles River two weeks later.

According to a civil complaint, Kelleher “showed obvious, outward signs of existing intoxication.” He can be seen on surveillance video in an impaired condition during the game.

Kelleher, 23, can be seen leaving the Garden at 10:01 p.m. after being captured on video sitting on the floor holding his head in his hands.

A toxicology report indicates that he had a blood alcohol content of 0.22%, according to court documents.

TD Garden and its parent, Delaware North, did not respond to requests for comment.