Nurse here.
I know it's probably too late, but I 100% agree with the recommendation to not transfer the LO out of their environment. And instead either hire agency aides (ie, from Home Instead or similar) OR send DH to LO's apartment to room in. (or DH looks in on your mother 1 hr away and -you- change locations to LO's apartment).
Your intentions are noble, truly, however you need to know that it's cruel for the LO with memory loss to abruptly move locations. Urine on chairs is the least of it. I would expect night walking, attempts to leave your home during the night, rummaging through cabinets [have you locked up the meds and vitamins?] and more.
There are very significant safety risks in this plan as described, unless you plan to sit at LO's bedside all night and alternate sleeping with DH. Ever heard of a Silver Alert? this is how it starts.
If you're determined to do this, despite the agitation it will invariably cause LO, then you really must buy a version of this bed alarm, to put under the bed sheet:
https://www.amazon.com/Smart-Caregiver-Bed-Alarm-Sensor/dp/B00489SJ4S?source=ps-sl-shoppingads-lpcontext&ref_=fplfs&psc=1&smid=A2TORNECBMNNW4&gQT=1
For your upholstered furniture, go the pet section of Amazon, or Chewy.com or in person at a chain pet store. Buy waterproof carseat covers like this. You can hose them off when you're done and give them to the regular caregiver of the LO for their own apartment OR donate to a dog fostering nonprofit or vet:
https://www.chewy.com/4knines-rear-fitted-seat-cover/dp/158385?utm_source=google-product&utm_medium=cpc&utm_campaign=20196576200&utm_content=&gad_source=1&gclid=CjwKCAiAjp-7BhBZEiwAmh9rBXug_BfYQ1H5cXCgyumRnjLTIoMRp5Z7IRVPbHrexDiYYJXucN8mihoCCXIQAvD_BwE
Again, I commend your instincts but -- as a person who takes care of people with memory loss -- I think this is a bad plan