Maynard Jr died almost a year ago on the tracks at Wimbledon tube station after fleeing police following a post-match drinking session with his Surrey team-mates. Post-mortem evidence presented at the inquest into his death indicated regular cocaine use over a period of several months as well as the presence of MDMA in the 23-year-old's system.
Those revelations dominated coverage of his death but Matthew Maynard told BBC Radio Five Live: "He has been made out to be some sort of druggie and he wasn't. That makes us angry because that wasn't Tom."
He added: "He was a good cricketer who loved the game. He made some poor decisions that night, in the house and in his car.
"We'll never know what went through his mind. Obviously, he took some social drugs but he wasn't the type of person who needed that kind of lift.
"We were absolutely amazed that drugs were involved. I find it astonishing that no-one else knew."
Tom Maynard was one of the game's rising stars, having represented England Lions and been tipped for full international honours. But his father is not prepared to consider what might have been.
"I haven't been there and I don't think I could," the former Glamorgan player and coach said, in an interview to be broadcast on Monday evening.
"It's great to see young players like Joe Root coming through for England but I can't allow myself to think, 'that could have been Tom'.
"You can't dwell on these things, otherwise you'll end up broken - and we already have been as a family."