Such outstandingly good advice here. I do want to amplify what Neverquit said about keeping the person in their own home with outside hourly helpers as long as possible. This is an excellent option between keeping the person in your home and trying to cope, and bowing to the inevitable and placing them in a home. Had I a relative needing such help, I would contact a school offering training for the Certified Nursing Assistant credential, or similar named occupations in other states. These programs are rather brief, usually about 8 weeks, but can be a fine source of motivated, mostly young people anxious to "help people". The going wage in Southern California is about $10-15/hour and even if you have to pay a registry, it isn't oppressively expensive.
This should work well if the person can manage some functions but as the degree of decline increases, it may eventually come to full time residence in a skilled nursing facility (referred to as a "sniff" (SNF) and the advice re urine odor being a failing grade was right on the money).
There does eventually come a point at which the most loving, dedicated relative can no longer manage a severely disabled person, especially if the person has moments of physical or verbal abuse directed at the family. No feelings of guilt should accompany a careful decision to place a relative in a care facility at this point. You gave it your best shot. Now, it's time for shift workers to take over and deal with the problem for their 8 hour shift and then get their own relief, while you get yours.
Ralph