Soul sleep or heaven which is the truth?
The scriptures are very clear that to be absent from the body (dead) is to be present with the Lord (in Heaven - since His finished work which allows us to enter that place).
It is clear that Paul's reference to "sleep" refers to our slumbering body which awaits glorification and not to our "soul".
When we sleep in this life we do not enter a state where our brain (analogous to the soul in this case) goes flat line and has not activity. That simply isn't what sleep is.
Sleep pertains to our resting bodies only - while our mind is very active. We dream while we sleep and often (particularly in these end times) receive information from God Himself.
The reason that hard line Adventists insist that all aspects of our nature go "flat line" or cease to function at all when we die - is because for us to go into the presence of the Lord requires that we are saved (justified) even now and do not await some time in the far off future to attain that salvation.
They do not believe, as the scriptures clearly show us, that we are justified and seated with Christ even now - reigning in the Kingdom of God according to our faith.
They believe that salvation will be meted out at a final investigative judgment when our lives (works) will be examined to see if we are worthy of salvation.
In hard line Adventism - worshiping on Sunday (as most of us do) is taking the "mark of the beast". Thus those so doing that sin (and other sins perhaps) will disqualify us from the salvation available to us.
This - of course - is not evangelical Christianity and is not the gospel of of grace which most of us believe in.
To the extend that an Adventist believes and teaches this hard line "soul sleep" doctrine - that person has fallen from grace in that he is teaching another gospel (a gospel of works) - which is no gospel at all.
Contrary to this false doctrine - the scriptures testify that we are saved by grace through faith and those believing in this life on Christ as their hope of salvation will pass from death to life and will never again come into condemnation.