When to re-home a pet of an elderly parent who is refusing to do it?

Your mom doesn't even take care of herself, no less the cat. Why have the cat suffer? Be merciful and rehome it. Then you also won't have to be cleaning up pee. Can you first take it to a vet to get checked to make sure it's not actually sick? Or, try PrettyLitter which turns color indicating a problem (my family uses it and it works). Sorry, this is such a sad decision and I know you mom "loves" the cat but let's be realistic: she's no longer able to take care of it.

This is probably not what you want to hear, but the mere fact that your mother does not want to give up the cat shows that the cat is important to her. If she has dementia, she's already living in a frightening world. I think taking the cat away from her would be hurtful and perhaps even harmful to her. I would probably do whatever I could to comfort someone who's old and scared. And what about the cat? Animals don't like being moved from their home any more than children do. I just wouldn't do anything about the cat. I think your mom needs it and it needs her.

Cats can get depressed and peeing may be the only way of communicating that the cat needs some attention. I bet the peeing happened when the litter box was too filled to use, it would like us using a bathroom where no one had flushed the toilet in awhile.

No-kill animal shelter are successful in re-homing adults/senior cats. Our last two cats we adopted when they were 9 and 12 years old. They were so happy to have all the new attention =^..^=

If Mom has Dementia she should not be alone at all. Not taking care of the cat means she can't care for herself. I personally would not want an old cat. If its started going in the apt it may keep that up especially if a new place.

Hi,
Cats can get UTI's and start peeing in new spots. Or they will do that because of stress and changes in their envioronment.
It can help to set up a second litter pan near where they peed. Might need a vet checkup.
Someone coming in and checking on your mom daily and doing the scopping would help, if the cat's healthy.
What kind of care would your pre-illness mom want for this poor cat, who through no fault of it's own now has an ill owner incapable of empathy due to her disease and no-one to take care of it consistently? Can someone in the family adopt it?
If not, look online for local rescues- most have a precence on Facebook. Or call the local animal shelter or the vet's office and ask for names of local rescues. If you use Petfinder or Pet Tango to search in the zip code, the animals that will show up will have the names of their affiliated rescue.

If you want to keep the cat in the home with mom I would have someone come in daily or at least every other day to do some "light house cleaning" this includes the litter box. A caregiver (paid for by mom) could do this as well as taking care of mom a bit.
OR
Tell mom that you noticed an "off odor" in the urine or blood in the litterbox and need to take the cat to the vet. Once that is done you can rehome the cat. (there are no kill shelters, please do not euthanize the cat unless there actually is a medical reason)
Clorox has a product called Urine Out and there is another product called Odor Ban that will be useful taking the urine and odor out of the carpet. It is possible though that carpet and possibly flooring might have to be replaced. (once urine gets into sub flooring it is almost impossible to get the odor out.)

How about on the alternate days when family is unavailable, you hire someone to help your mother? Pay someone to clean the litter box and to tidy up around the apartment.
Your mother is in the last days of her life at 94 and with cancer. Don't take away the cat who is her constant companion regardless of whether she sleeps much of the time or doesn't. That's cruel. Hire someone to go to her place on the days when family members are unavailable.