So why don't you speak with Gizzy first and then let him out of his crate? and while he's out, then take out the blanket. Don't know why he's hissing---want my blankie in the crate with me? you don't say hi or speak to me? bored, and have to do something......who knows, but it doesn't seem as if he's startled, maybe more like mad or upset you're taking out the blanket after he spent a lot of time pulling it in there. Maybe he wants to see out? or wants to lie on it bunchedup (my cats like to do that). Does he pee on it? IMO I don't think there's a medical reason Gizzy is hissing. Most cats hiss because they are scared, startled or annoyed.
Am sure you'll find lots of advice on the forum re dogs, or Huskies in particular.
Sorry to hear about your bf's grandmother, hope she'll make a good recovery. As for her house, remember that saying "don't count your chickens before they hatch". Who knows what will happen there?
"We humans are indeed fortunate if we happen to be chosen to be owned by a cat." -- Anonymous