An inquest into Brandon Daniels' death heard that he was in Saskatoon with his cousins when he got separated from them on the July long weekend in 2010.
Justin Daniels said his cousin had not slept for about 24 hours as they had stayed up playing video games.
He says he didn't see anyone take drugs, alcohol or prescription medication during that time.
Justin says Brandon left to go downtown with two other people on July 2 and never came back.
The inquest has already heard that Brandon Daniels died from an overdose of Tylenol, but police thought he was drunk.
Justin said he was aware that Daniels had been hospitalized for mental health issues prior to their trip to Saskatoon, but did not know the details of his condition or notice any abnormal behaviour the weekend he died.
"The last time I seen him he was fine," Justin said, wiping tears from his face while he passed a picture of Daniels to the jury that he had taken about six hours before he last saw his cousin.
Sgt. Randy Huisman, who investigated the death, said Daniels had been having psychotic episodes and was admitted to a mental health facility in Prince Albert that year.
"He didn't have his medication; he knew medication worked because that's all he was told, 'you have to take your medicine.' He knew it helped him ... so he was trying to replace it," said his mother, Sherry Bird.
Const. Sean Dexter was one of the officers who took Daniels to detention. He testified that Daniels was slouched over on a bench beside a puddle of vomit and wasn't responding.
Dexter said he appeared drunk, so he arrested him for public intoxication. Police booked Daniels into detention without doing a medical check.
Sgt. Huisman said a junior officer with paramedic experience thought something was wrong with Daniels but didn't say anything to detention staff because she didn't want to question higher-ranking officers.
The decision not to do a medical check essentially lead to Daniels' death, Huisman said.
Also on HuffPost