Katrin's choice: how do I tell my son about great-uncle Heinrich. . .?

A fascinating piece in the Times:

KATRIN HIMMLER’S son is a bright, curious six-year-old. “I’m dreading the moment,” she says, “when I have to tell him that one half of his family tried to kill the other half.”
Frau Himmler, a political scientist, is the great-niece of Heinrich Himmler, head of Hitler’s SS and mastermind of the concentration camp system that murdered millions of Jews.
She is married to an Israeli whose family was confined to the Warsaw ghetto, which was burned to the ground by troopers acting on her great-uncle’s orders.
Sometime soon her son will have to be told of the 20th-century tragedy that is part of his heritage. Katrin Himmler, 38, has tackled the problem by writing an account of the family which she will give to her son as soon as he is old enough to read.
(snip)
Frau Himmler’s father was a nephew of the SS leader, the most sinister figure in the Nazi leadership. He could not find the vocabulary to answer his daughter’s question: “What does it mean to be a Himmler?” He instead gave her books on the Nazi era. “Then came the television film Holocaust,” she said. “I was 11. I sat at my desk, crying and crying because, of course, the name Himmler was repeated again and again.”
There were three Himmler brothers. Katrin’s grandfather, Ernst, died fighting in the closing days of the war. A second brother, Gebhard, was held in an American prisoner-of-war camp.
Heinrich was caught by British troops near Hamburg. He was in a sergeant’s uniform, an eye patch replacing his pince-nez glasses. During a body search he bit on a cyanide capsule.
Frau Himmler had to reconstruct the family relationship from these abrupt endings, and as she trawled her family’s collective memory she encountered resistance. Heinrich Himmler’s daughter, Gudrun Burwitz, continues to cherish her father’s memory. She was the guiding spirit behind Stille Hilfe (Silent Aid), a charity which funnelled money to relatives of war criminals and which encourages neo-Nazis. “