I respect where you're coming from. I don't disagree with you necessarily. But is what you're saying in the best interest of him, or the best interest for society? There would be a lot of free men released into society if we made decisions based on the potential we think people have.
If you, or anyone or anything, can reform such behaviour, I'm all for it. I would rather see him changed and become a better human being. The same way (to make it personal) I would like to see my 30-year old brother change his life around, because he has the potential to do so because he has the same blood as me and we went through the same challenges in life (jail, addiction, being violent), although I'm 6 years younger. I conquered my demons and persevered, and my brother is the same person he was when he was 18. There is a point where you have to draw the line and make a decision based on what's best for the collective, and not the individual and said individual's (positive) potential. If people collectively drew that line with my brother when he was 18, or arguments sake lets say 21 when he is more of an adult and had a chance to "grown up", there would be at least 9 years of harm to society prevented. Harm which includes dozens of unjustified beatings, many who were hospitalized and one who was put in a coma. Harm that includes every form of abuse to his baby mama and other women. Who knows what he is doing now. No one in the family now has contact with him anymore, and before they cut him off, they let his behaviour slide because he "wanted to change" and he's "trying to be good".
The difference here is this guy clearly doesn't want to change, and therefore I personally believe no special exceptions should be made because of the potential you think he carries. There is positive potential and there is negative potential, and evidently we are seeing which potential is outweighing the other.