why is mom on your couch? do you handle all the expenses, is it your place?
does mom have her home?
there are other siblings, why is she not there?

if there are other places to stay, have her get off your couch (if you are financially independent) and go to their couch. with the cats. all of them.

are you an adult? then your meds & diagnosis are your business not hers. doesn't really matter if she believes or not, it makes it easier but her belief doesn't make it necessary.

siblings talking to you are nice but you can manage on your own. of course she doesn't want them talking to you.. you might tell them to take her in. which you should at some point. share the wealth , with mom being the wealth. it is not going to be easy but if you want your couch, house, & freedom you will have to stand up and speak out, with a strong back bone. mom sounds like she is con trolling and has it all figured out.