JW sins are held in abeyance, so to speak, and paid for upon their death
I do not know the JW beliefs, in fact most JWs don't know them ("Jesus is the mediator for only the 144, 000" for example) but if this is the current light™ then one verse shows that up for the falsehood it is
Ephesians 2:1-7 (New International Version)
Made Alive in Christ
1 As for you, you were dead in your transgressions and sins, 2 in which you used to live when you followed the ways of this world and of the ruler of the kingdom of the air, the spirit who is now at work in those who are disobedient. 3 All of us also lived among them at one time, gratifying the cravings of our sinful nature and following its desires and thoughts. Like the rest, we were by nature objects of wrath. 4 But because of his great love for us, God, who is rich in mercy, 5 made us alive with Christ even when we were dead in transgressions—it is by grace you have been saved.
6 And God raised us up with Christ and seated us with him in the heavenly realms in Christ Jesus, 7 in order that in the coming ages he might show the incomparable riches of his grace, expressed in his kindness to us in Christ Jesus. Or this verse
Colossians 3 (New International Version)
Rules for Holy Living
1
Since, then, you have been raised with Christ, set your hearts on things above, where Christ is seated at the right hand of God. It is all past tense, all done, the ransom has been paid in full already and I sit in the heavenly realm with Christ at the right hand of the Father. All that one need to do is ask make Jesus Lord. This WT doctrine once again denies Christ' sacrifice and His Lordship. "Jesus is Lord"
Romans 10:9 1 Corinthians 12:3 Believe, profess and act accordingly-simple. All the best, Stephen