Scripture is silent on the awareness of the Christian upon death. Second Corinthians 5:1-3 tells us about being clothed with our heavenly habitation, which will release us from the burdens of mortality. Verse 8 provides us with a particularly heavenly perspective: "To be absent from the body [is] to be present with the Lord."
Luke 16 speaks of the rich man asking someone to go to his family to warn them about their impending doom. However, his request is based upon his lifetime recollection of his family's lack of spiritual life and not necessarily on his observing earthly events after he died.
Likewise, 1 Samuel 28 describes a rare and unusual occurrence where someone from the dead came back to respond to one yet living. God allowed Samuel to communicate with Saul, though Saul was wrong to seek the help of a medium to begin with. Scripture forbids that practice (Deut. 18:10-12). Samuel's responses do not describe current conditions; they are based on a message he apparently received from God that Saul and Israel would go down in defeat (1 Sam. 28:15?19).
Some teach that our deceased Christian loved ones can see us from heaven. They frequently cite from Hebrews 12:1, which says: "Therefore we also, since we are surrounded by so great a cloud of witnesses, let us . . . run with endurance the race that is set before us."
They interpret that to mean our departed loved ones watch us like spectators do in a stadium, seeing our every move and cheering us on. While that may seem comforting, we don't believe the Bible is really teaching that.
The witnesses in that verse are not modern-day loved ones, but the faithful saints in Hebrews 11 who lived victorious lives by trusting God. Those saints are witnesses to us because their lives testify about the value of trusting God no matter what hardships we face. They are active witnesses who speak to us by their example; not passive witnesses who watch us with their eyes.
Consequently, when we understand Hebrews 12:1 in its context, we realize that it doesn't really support the idea that our loved ones are watching us from heaven. Our comfort comes not from knowing they can see us, but that they can see Jesus and one day we will see Him with them as well-never to be separated again.
For more information on heaven, take a look at John's book, The Glory of Heaven.