Tom makes clear that sleeping and dying, when done prayerfully, entail an act of trust in God. Of course it is quite possible, indeed it happens all the time, that people sleep and die as unbelievers. They do both just because they have to, attaching no further significance to them. Even so, sleep as opposed to fitful dozing does entail a kind of trust. One who sleeps well trusts that nobody is going to come and victimize them as they sleep. Perhaps that's a kind of natural catechesis about death. If we trust that reality is ultimately beneficent, we can die well even if we don't know a benevolent source.
The Resurrection enables believers to have that trust. Most unbelievers don't have it, and when they do it's because they know the truth under another description. Maybe that's why so many health-care dollars are spent on people in the last few weeks of life. But it doesn't have to be that way. The late pope showed us the right way.