How does DD know what Petunia/Vernon said?

[abergoat]

No: HPFGUIDX 156697

Brothergib wrote:

> How does DD know that Petunia/Vernon is about to throw Harry out of 
> the house?


Abergoat offers this quote:

    "I thought," said Dumbledore, inclining his head slightly, "that
she might need reminding of the pact she had sealed by taking you. I
suspected the Dementor attack might have awoken her to the dangers of
having you as a surrogate son."
    "It did," said Harry quietly. "Well - my uncle more than her. He
wanted to chuck me out, but after the Howler came she - she said I had
to stay." 

Abergoat adds:

I believe the implication is that Dumbledore heard about the dementor
attack (and Dudley's involvement) and just guessed that the Dursleys'
concern for their son might make them try to throw out Harry.

Abergoat