I'm having a very hard time with understanding why my friend's dog sleeps too much. There's never a time when I visited him that his dog isn't sleeping. Even if he wakes up and walk about a little, it would go back to sleep. Could it be sleeping sickness?
If my dog sleeps more than the ordinary, I would be taking him to the vet immediately. It's definitely a bad sign that something is wrong with him and it needs to be taken care of as quickly as possible.
Just like human beings, when one sleeps too much, it's either a sign of sickness or too much stress or even being pregnant if it's a lady. The same thing is applicable to dogs too. They are almost the same thing as human beings too.
If it's not a health problem, then the dog must just be tired and it's the reason why you see it sleeping all the time. Also, you need to find out if the dog stay up all night performing security guard, if yes, then it's a normal thing for the dog to sleep during the more hours.
Usually, if your dog is sleeping more than they usually do, that could indicate that they are unwell. If you find your dog to be sleeping more than they should be, I would take your dog to the vet to be on the safe side.