If the Catholic Church wants the end of the death penalty, then the Catholic Church should build and operate a facility for those sentenced to death. The only prisoners in there would be those under the sentence of death. But then...here we come to the rehabilitation part. Wouldn't these people have to form their own community where they were doing meaningful work, taking care of each other by doing the cooking, cleaning, laundry, etc. AND bringing in work to finance themselves (license plates, sorting garbage for recyclables, writing their life story with all proceeds going straight to the prison community on individual pockets, etc.
Which brings us to the question of what happens when one of the inmates begin killing other inmates in the prison.
In providing and maintaining this facility, by necessity, the Church would have to provide medical and psychiatric along with the spiritual help.
Again, my main point is not that the Church is calling for the end of the death penalty--but is calling for it without lifting a finger. If the Church believes ending the death penalty is what God is asking for in this day and age, then the Church itself should be leading the way, and figuring out all--and how--this is to be done, and doing it without help as it is the Church's grand idea. While I applaud the idea, I am disgusted that the Church is calling for someone else to take care of this. I (a Catholic) call for the Church to put up or shut up. (And I'd have so much more admiration and respect if the Church does the former.)