Not necessarily. My "little one" has reached her 110th birthday and has been sleeping a lot since she was 99. It is painful to take bloods in an elderly patient, however take blood sugar and have the physician take a thyroid test. Genetically, some people sleep a lot and others sleep very little. I can get on on two to three hours sleep a day, as could my father. Others like to snooze like contented kittens all day long.
A lot of older people do sleep a lot, but not necessarily all in one go. If he is feeling ill he will not have any inclination to do anything.
If you are concerned about your father sleeping a lot, have a chat with the doctor. It could be that some of his medications he is on is making him sleep, or he may have lack of iron that has caused anaemia. This can be quite a problem because the elderly do not always have all the necessary minerals and vitamins that the body requires to function properly.
All you can do is keep him as comfortable as you can and give him what he likes to eat and drink. As you have not said whether your father has an illness, then you will know what he is allowed to consume or not.