User blog comment:Donut4/ANOTHER QUESTION!/@comment-76.1.99.51-20120328071320

Mr. Weasley had no idea what Harry and the others were up to, specifically. Do you really think they would've asked him for help and revealed their quest after the scene with Lupin? None of the Weasleys know anything other than "Dumbledore left us stuff to do, and it's private." What would be the benefit of putting Mr. Weasley at risk by revealing their true identities to him? In the Ministry, you never know who or what is paying attention.