Jean-Pierre Ménard, the lawyer representing the Bertrand family, is suing the Centre Notre-Dame de L'enfant rehabilitation centre for $241,000.
In August 2010, Diane Bertrand and her husband took their 33-year-old son, Sébastien Roy, to the centre in Sherbrooke for a two-week stay so they could take time for themselves.
Sébastien, who needed constant care, suffered from severe mental impairments and epilepsy. According to a coroner's report, he drowned after having a seizure while taking a bath unattended.
According to court documents, first respondents attempted to reanimate Sébastien but were unable to do so.
The coroner's report states staff at the Centre Notre-Dame de L'enfant did not give him his medication for epilepsy despite being told to do so in hand-written notes left by his family.
The rehabilitation services director, Carolyn Léonard wouldn't discuss the report.
Ménard said he hopes the lawsuit will lead to improved care and services across the province.
"Because they receive so little services, they fear to lose what they receive," said Ménard. "Unless it is a very very dramatic situation, people will be very reluctant to complain."