yeah she lives with kaoru and zelda now! july was such a wash for me HAHAHA... but in any case i'm very happy to talk out anything you might have wanted to handwave re: those two weeks. yako would probably have been pretty accommodating of the 'hey this is koga and he's gonna live with us for a while' escalating into mild alarm when it's like 'haha yeah pls don't be concerned ....... that he's sleeping a lot........ in rei's coffin?????'

it's up to you how much they would have interacted during that time -- she probably would have been courteous/mindful enough to offer to take him meals to his room if he's clearly feeling unwell, and she also could have put some enchantments into the food for strength/good health etc if he was willing to eat it. i'm not sure if she ever got the full lowdown on him being a vampire, so let me know if you'd prefer that it remains ambiguous for now (just assume she didn't see enough of him to put the clues together) or if she would have been directly told by him or anyone else what exactly he's going through.