The late 'Thriller' star - who died from an acute Propofol intoxication last June - was honoured with a special musical tribute to mark being given a posthumous Lifetime Achievement Award but organisers failed to invite his siblings, including those who performed in The Jackson 5 with him, to the star-studded music awards show in Los Angeles on Sunday (31.01.10).
His brother and former bandmate Randy tweeted: "So proud, my brother being honoured tonight with the Lifetime Achievement Award. My family would love to be there but, truth is, we weren't invited.
"Do you want more truth? Let me be clear. When I said 'my family' I meant my brothers, sisters and parents."
Michael's three children, Paris, 11, Prince Michael I, 12, and seven-year-old Prince Michael II - aka Blanket - were there to honour their father but Randy is convinced the children were only invited as an afterthought.
A source told the Daily Mirror newspaper: "Randy was incandescent. He believed the Grammys only thought of including Michael's children at the 11th hour as dad Joe Jackson complained there was no family representation.
"The brothers were hoping to attend and wear their silver gloves and matching suits to honour their brother. They feel insulted and hurt that they have been snubbed in this way. Michael would've wanted them there.
"The Jackson 5 was where the magic began. They're a huge part of his story and felt they had been horribly overlooked."
The eldest children took to the stage wearing black suits with red armbands to accept the late 'Thriller' singer's award - which he was given for his contribution to the music industry, while Blanket remained backstage with his grandmother Katherine Jackson.
A source said: "Michael's children themselves decided just Prince Michael I and Paris would speak on stage and accept the award on behalf of their dad."
Meanwhile, Michael's older brother Tito - who along with the 'Billie Jean' star, Randy, and siblings Jermaine, Jackie, and Marlon had performed with The Jacksons - is being sued after allegedly failing to perform at a tribute show for his brother in the US.
Promoter Roy Isaac has told Tito to repay the Â£4,700 he was paid for the concert within 30 days or he could face legal action.