I don't quite trust him either and yes, you can use my rooms. I think I'm on the tail end of the Pox -- the hallucinations are no longer as severe as they once were. When does he wish to come and make this report?
I would not doubt it for a moment that the Lestranges were behind the illness. It seems exactly like their flavour. What concerns me, though, is they did not use this as an opportunity to make an attack.
There is still something fishy about the whole ordeal and I do not like it one bit.