I do think one day he could be rehabilitated but I don't think he should ever be released from prison as he could still one day if he did get out of prison go back and commit another shooting.
I feel bad for him as he was seeking help and didn't get it and feel bad that he made a bad decision and wish he never did it.
But he still is a threat to society and we can't trust him anymore so he needs to remain in prison for the rest of his life to protect society from him.
It's a sad situation that we even need jails and prisons and I wish everyone would be good and not harm one another.