They will die without Christ . They won't be glorified..In calvinism there is no good news . They can't tell a person that Jesus has died for their sins and was raised for their justification.Justified by His blood, Romans 5:9
That's the atonement, and that atonement only justifies the one who believes Him. The one who does not believe Him, not justified = not atoned for: therefore they will die in their sins.
He glorifies those He justifies, and those He justifies are those who believe, and He justifies them by His atoning blood.