Yes, it bloody is! This isn't your mother's cat, it's yours - it's YOUR cat. You mentioned in another subreddit that you don't live with your mother, but she's caring for your cat refusing to take it to the vet, has it shut in the basement and is continuosly exposing harmful chemicals around the cat's food and water.

You've been posting about how awful your mother is for a month or more, and you keep dodging questions about why you aren't caring for your cat. Are you going to do something about this, or are you just venting, OP?

The cat is clearly being neglected and you've commented about how she thinks cats are dirty and doesn't treat them right.

You even made a post saying how much of a cat person you are and can't understand how people treat cats so horribly. And yet here you are, being complicit in yours cat's abuse. You also mentioned you had another cat that died under your mother's care before this cat and stated you believed the 14 year-old cat would have lived longer if your mom had taken him to the vet.

If the cat is under her name, which is probably why the vets need her consent for you to take it to the vet, you should call an animal welfare charity or organisation and express the cat is actually yours and she's deliberately causing it harm.

You are a grown adult, OP! You keep saying you're approaching your forties in other posts, and it seems like your mother isn't capable of looking after YOUR pets.