Brian Kirby was detained for questioning after James Hughes' body was discovered in a garden shed but released two days later without charge. In his first public statement, he thanked police for their "sensitivity," The Guardian reported.
Hughes, 22, had the mental capacity of an 18-month-old. He was not reported missing until his mother disappeared and investigators are still trying to determine when he was last seen.
Heather Wardle, Hughes' mother, was found dead in a wooded area near the family home in Redditch, Worcestershire. Kirby described her as "a devoted mother and partner."
"He brought something special to everyone who had the privilege of knowing and meeting him," Kirby said of his stepson. "He was a son, brother and friend, and will be dearly missed."
Friends have speculated that Hughes, who suffered from epilepsy, died of natural causes and that Wardle concealed the death out of grief and feelings of guilt and then took her own life. Police have not yet determined how Hughes died.
Trader Joe's: Car crashes into Long Island store, injuring 11
Ukrainian protestors topple Lenin statue [VIDEO]