The Diff'rent Strokes star passed away on 28 May (10) after suffering a brain haemorrhage following a fall at his Utah home.
The former child star cut all ties with Willie and Edmonia Sue Coleman in 1989 after successfully suing them for misappropriating his $3.8 million (£2.53 million) trust fund. He had had little contact with them since the case was settled in 1993.
But his folks are still upset about the actor's death and they admit they had to hear the sad news about their son on TV while they were at a family gathering.
Edmonia had to phone around to get a desperate message to the actor's ex-wife, Shannon Price, who was with Gary when he died.
Speaking on the Today show, Edmonia recalls, "We were with some family celebrating my husband's brother's 76th birthday in Arkansas and we got the news there. Didn't know what to think. I didn't know who to call, who to get in touch with, what hospital he was in, or anything.
"So I called the sheriff's office in Utah. I said, 'I'm Gary's mum, I understand that he's critical. Can you please get in touch with his wife and ask her to call me back?' She didn't get back on that day, but a couple days after."
But Willie is angry at how long it took Price to reply and he admits he was surprised at the lack of emotion she displayed in the voicemail message she left for them.
He fumes, "First of all, she didn't call us, she didn't talk to us direct. She had called and left a message, the most strangest message I ever heard in my life. When someone is hurting, like we was at that time, to leave a message, like, 'Hi, this is Shannon Price. Thank you for your interest... If you need more information, my brother is handling the arrangements.' She left a message but no return (number). The next day she leaves a call back number."
Edmonia admits they are still not completely sure of the circumstances surrounding Gary's death: "We have listened to the 911 tapes. I can't say we actually know everything, but I do feel a bit better because we got a report from the coroner, the authorities, that said there was no foul play, so that made us feel a lot better."
The couple refuses to jump to conclusions and blame Price for the tragedy - because they accept Coleman's health was fading fast in his final months.
Willie explains, "We've never pointed the finger at Shannon because his body had come to the point where it had come to the pyramid of sickness, where he had no kidneys... it wasn't working."
The star's parents were officially named as Gary's next of kin, but a planned funeral was postponed last week (04Jun10) after a battle emerged over custody of the actor's remains. The Colemans insist they just want to see their son laid to rest.
Edmonia says, "I want all the talk to stop. Gary's gone. I want his body put away respectably so we all can bring some closure to this part."
A tearful Willie adds, "That's one of my wishes. If they want to bury him or cremate him, please, by all means, go ahead and do that, because his soul is with Jesus. But it's his spirit that's not gonna rest until he's laid to rest."