Is this your own speculation or does it have some basis in Catholic teaching? You are making many assertions here such as angels being unable to change their minds. If that is so, how do they have free will?
The angels do have free will, it just doesn’t operate in a way we understand. We see free will as a successive series of choices within the bounds of our temporal reality. I can chose for God or I can chose against him. I can repeat this process over and over again until the time I die.
Angels, on the other hand, had one choice. They were completely free in that choice, but once the choice was made it could never be revoked. This is not because God locks their willing in place and removes their free will; rather, it’s because of their nature as angels. God created them full of His knowledge, this means that they had a complete understanding of the consequences of their choice when they made it. They saw every last aspect of what that choice would mean. We, by comparison, barely have any idea of the effects our choices will have.
The result of the angels’ complete knowledge is that their choice is perfect. This doesn’t mean that they all chose well, it just means that they chose with a full understanding of what that choice would mean. As a result, it is impossible for some new piece of information to be discovered or new event to occur that would influence that choice. If nothing can happen that would influence that choice, then there’s nothing that would bring about a change in the decision. As such, the angel’s decision is locked, as is our at the end of our life.
With us, it’s a bit different though. We do not have perfect knowledge, so we can sway back and forth between choosing for God and choosing against him. All of these choices have an affect on our soul, shaping it and molding it one way or the other. When we die, we see God in his entirety and are confronted with the reality of our lives and choices. If we’ve shaped our souls towards God and are open to his forgiveness then we are frightened by this reality, but we know that Christ will advocate for us and intercede on our behalf, and he will help us to accept God’s limitless mercy. If we’ve lived our lives without taking advantage of God’s mercy, or if we die in a state of mortal sin having chosen to cut ourselves off from God through our actions, then we will be unable to accept that mercy, and will cast ourselves into Hell because we cannot stand to be in God’s presence knowing the full brunt of our sinfulness and the pain it has caused Him. If we are unrepentant sinners, then not only will we not accept God’s mercy, but we will reject his authority outright, and demand to be separated from him so that we will not have to be subject to his authority.
These three potentials are not dogma or anything, but they’re a common way of expressing the potential outcomes of our particular judgment which I find to be very helpful.
As for your question about Catholic Teaching about what Hell is, I don’t have the specific paragraph, but the catechism states pretty clearly that the chief pain of Hell is the absolute separation from God the souls experience. Keep in mind, this isn’t like being apart from a loved one here on Earth. God IS Love and Goodness, he is the source of everything we know of these realities. When we cut ourselves off from him we are separating ourselves from
any experience of these things. To be separated from God is to never know happiness, never know goodness, never know peace, love, or rest. It is to be empty, devoid of meaning or purpose. It is total separation from even the faintest glimmer of light and hope. It is eternal and absolute despair, one of the greatest tortures of which I’m sure is the knowledge that it will never end. Simply saying that we are cut off from God doesn’t do the reality of Hell justice.
