{{Anne}} It makes me smile to think of your grandmother going out for champagne and Belgian waffles in her final weeks. That's just wonderful.
IIRC, liquid fabric softener is bad for water resistant materials (or anything with a specific reaction to water - wicking high tech fabrics and whatnot) because it works by making the clothes you wash in it more absorbent, somehow. And the sheet things have the opposite effect. But I get confused about what you aren't supposed to use on which and mostly just don't use either.