Your relationship to the person on whom you are spying matters. If that person is your child or your employee, you have a lot more leeway when it comes to monitoring their activities. If you think someone is spying on you illegally, file a report with local law enforcement so they can investigate your case.
Most cats snooze around 16 hours per day. The majority of their sleep time, however, is much shorter than the typical seven hours or so that humans average at. night. Cats tend to sleep lightly, without going into a deep sleep.
Newborn kittens sleep almost all the time. In time, kittens start sleeping less and less, until their sleeping hours are equivalent to 16 hours. The sleeping hours depend on the cat's age and lifestyle. If he is left alone all day, your cat is more likely to sleep and keep awake at night.