You need to give some more details if you are looking for an answer to a question. If you want to do some background reading, click on 'care topics' at the top right hand side of this screen. It will come up with an alphabetic list. Scroll down to 'sleep issues' for lots of information. Among other things, a large increase in sleep can indicate that the end of life is nearing.
Depending on the particulars, the first things I think of are depression or over medication. But no way to know....