So even if this were to work as described, the now un-dead person would have no memory of their past life, and would be like a child in an adult body. This would create more problems than it presumes to solve. The grieving family would not really get their loved one’s ‘back’. The soul of that person would still be dead and gone. This should make some good movie scripts for actors like Johnny Depp, Nicolas Cage or Kenau Reeves.
The soul being dead is another issue. Yes, getting them back would cause infinite new problems unless resurrected as Lazarus.