The atman/æther/akasha is eternal and an endless sea and can never be erased. This is the fundamental foundational energy of the universe, and this is the energy that your soul is made from. It is true that this energy can never be destroyed. But the way that this energy is programmed may change, it may change into other forms and patterns that are different from how it started. This energy can be imprinted with forces to be carried into certain actions and directions. And these forces may become weak and get erased. Or these forces may be overpowered by other stromger forces, and end up going into a different direction.
It is not true to say that a person's soul can not be erased and dissipated. Your soul is a very specific organization and manifestation of this energy. With very specific energies and directions programmed into it. Everything that makes you yourself, and not someone else. Your entire history, all of your karma, all of your energies and forces and directions. These are all programmed into your soul. Somebody who is weak, who does not take good care of themself, who gets weaker and weaker each generation. The energies of their soul, the programmed forces that make them themself, are getting weaker all the time. And eventually there will be nothing holding them together, and they will dissipate and stop existing. This is what we mean by their soul being destroyed. If there are no longer anyany forces that make them themself, then they don't exist anymore.
Think of a little ice cube floating in an ocean of water. The ice cube is its own object, its own established form, its own self. Now if it melts and dissipates into the water, then it is gone. It doesn't exist anymore. It is dead.
Or think of a balloon. The rubber of the balloon is like the individual specialized energies of the person's soul, and the air inside is like the akasha that it is made from. Now if the energies of the person's soul weaken and disappear, think of that like the rubber of the balloon disappearing. And now there is nothing to hold that air together anymore, and it all dissipates back into the atmosphere. The balloon does not exist anymore, the form that it once was is now dead and nonexistent.
Your soul is a very specific form and shape, and this form may die and disapear after generations of weakening. If it gets too weak, there is nothing holding it together anymore, and it is gone. This is what it means for a soul to be destroyed. The æther/akasha/atman that the soul was made from is still existing, now in a blank and undefined way with no shape. But the form of the soul is destroyed and gone. I hope this made sense this way.
