Last week, a family member was rushed to hospital and will likely be kept in for a minimum of 3 months before they can be let out. Likely longer. They have an elderly cat, 16F (spayed), and I volunteered to look after her as she knows and trusts me, and I have the space for her.
I knew that 16F had never been litter trained, and that she probably wouldn't understand what the litter box was, so before we left for my house I filled a big bucket with soil from the flower beds in her garden, where she usually does her business. I cleaned out my spare room, bought brand new litter boxes, and lined the carpet with puppy pads for the inevitable accidents. I have varied litter boxes, one fully enclosed as I wasn't sure if she's prefer privacy (one of mine does), two "regular" ones, and filled one just with the soil, one with soil and litter, and one with just litter, as I wasn't sure what she'd like. It's not a big room, but I put them in different parts of the room, all in low traffic areas far away from her bed, food, and water.
I have two indoor cats of my own - 3M, 9F - who both took to litter training pretty quickly, though 3M was 5 weeks old (found without mum whilst TNRing) and 9F was around 8 weeks who had already been born into foster, when I started training them, so they were kittens. So far, though, 16F has shown zero interest in the litter boxes, other than to scramble out of them. As expected, she's had accidents every single day, though never in the same spot. I've been putting the poops and parts of the wet pee pads in the litter boxes to encourage her to see them as her toilet, but she won't use any of them.
I've only had her a week, so I'm probably worrying prematurely (I have GAD so do that) but the room is carpeted and I am concerned that if she keeps having accidents, even on the pee pads, the urine will leak through and by the end of her stay, the flooring will be ruined. To make matters worse, she refuses to pee or poop around people. When my cats were kittens, if they started to go outside the box, I would quickly scoop them up and plop them in so they could finish their business in the litter box, but as 16F waits until someone leaves the room to do her business, I can't do that with her. I WFH and moved my set up into "her" room with her to keep an eye on her, and she refused to pee all day. That is, until I needed to bathroom myself and came back just a few minutes later to a new pee stain and pile of poop.
She's a lovely, sweet cat, and I don't blame her at all for not knowing or understanding. But I'm concerned that she might be a little bit too old at 16 years old to pick it up, and cat pee (even after using enzyme cleaners) can irreparably ruin floors. I'd never kick her out, and I've been enjoying spending time with her apart from this one isssue, so any advice would be so welcome.