16yr. old cat

Question
my sister has a 16 yr. old cat. she had stopped
covering her litter after eliminating. is this normal for her age? also my sister keeps the litter dirty most of the time, but she says that the cat is old that's why she doesn't cover.  could she or any of us become unhealthy inhaling
odorous litter?

Answer
IF she doesn't keep the litter clean, the cat may very well STOP using the litter box.  I would recommend scooping the box daily and dumping the whole thing every week or so.  Even add another box.  Usually only very dominant cats won't cover their stools, however, in her case, she may not be covering because she wants to get out of the box quickly or doesn't want to dig in dirty litter to do so.  Inhaling the ammonia odor is not really pleasant for anyone, so tell you sister to get on litter box duty.  Would she want to go to the bathroom in a toilet that wasn't flushed after several bowel movements?  I DOUBT IT!