When mental and physical barriers feel insurmountable, often the care of our kitty suffers. This is heartbreaking to the person who is struggling as they love their pet children dearly. It may be the case that rehoming an animal you cannot care for is the most loving move if things are dire. However, there are solutions out there that may help you increase the level of care you are able to provide before taking the drastic step of saying goodbye to your loved one.
If you have a cat that is peeing on the floor or your clothes then their box isn't being tended to frequently enough. If you know me then you know that one of my favorite routines are closing duties. Closing duties are a short list of tasks I complete everyday at 7pm right after my kids go to bed. It takes me about 30 mins and then I stop and relax for the rest of the evening. I always suggest that you start small with this routine. Whether it's an opening duty first thing in the morning or a closing duty in the evening, scooping the litter box and feeding the cats is the perfect task to start with. The litter box is much less overwhelming when scooped daily. Setting a daily alarm on your phone or alexa can help with memory issues.
There are also some products out there can that can make the task easier. Click the underlined titles for links (these are not affiliate links)
Litter Genie: An odor free box that holds cat poo after scooping so you can take out kitty trash less often. Simply scoop, dump, and go.
Kittypoo club: A subscription service that delivers a disposable litter box with litter every month to help you stay on top of switching out the kitty litter.
Chewy.com: A subscription service that will deliver litter to you.
Automatic Litter Boxes: some people find the automatic litter boxes helpful because the scooping is done automatically. However, these boxes still need regular attention to keep them working and sanitary. Be sure to do some reading about them to see if they will be helpful to you. I've linked the Wirecutter article that outlines the best ones and the drawbacks too.
Automatic water fountain: Cats often won't drink dirty water. If bowls aren't cleaned regularly they may seek out water elsewhere, like cups or water fountains. An automatic water fountain with a filter can be of help to keep water fresher longer. Do some reading on how much upkeep one of these entails to see if it may be a fit for you.