From HowStuffWorks:
The Scout motto is “be prepared,” but it's hard to be prepared for death, be it our own or a loved one's. Too much is unknown about what dying feels like or what, if anything, happens after you die to ever feel truly ready. However, we do know a bit about the process that occurs in the days and hours leading up to a natural death, and knowing what's going on may be helpful in a loved one's last moments.
During the dying process, the body's systems shut down. The dying person has less energy and begins to sleep more and more. The body is conserving the little energy it has, and as a result, needs less nourishment and sustenance. In the days (or sometimes weeks) before death, people eat and drink less. They may lose all interest in food and drink, and you shouldn't force them to eat. In fact, pushing food or drink on a dying person could cause him or her to choke — at this point, it has become difficult to swallow and the mouth is very dry. As the person takes in less food and drink, he or she will urinate less frequently and have fewer bowel movements. The person may also experience loss of bladder and bowel control. People who are dying may become confused, agitated or restless, which could be a result of the brain receiving less oxygen. It can be disconcerting and painful to hear a loved one so confused in his or her last days.
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