JK Rowling's favorite fan theory is Dumbledore as Death in the Tale of the Three Brothers

This is the theory (quoted from this Reddit thread):
In the tale of the three brothers, Death gives a gift to each of three brothers. The first brother lusts for power, and gets an unbeatable wand. the second wizard lost a woman who he hoped to marry, so he got a stone to bring people back from the dead. the third brother wanted to not be followed by death, so he got an invisibility cloak. Voldemort represents the first brother, as he wanted to be the most powerful wizard in existence. Snape represents the second brother, as he lost Lily, the woman who he was in love with. And the third brother is represented by Harry, who simply wanted to continue on with his life free of dark magic. Death is also represented by a character. I believe the character is Dumbledore, and this is why:

1. In the story, Death had all three items Dumbledore was, at one point, in posession of all 3 items.

2. At the end of the Tale of the three brothers, it is stated the third brother greeted Death as an old friend. When Harry is "killed" by Voldemort, he sees Dumbledore at King's cross, and greets him as an old friend.

3. Voldemort's worst fear was Death, and Dumbledore is refered to as "The only one he ever feared"

Sources: 1 2
What are your favorite fan theories, ONTD?