It doesn't get any sicker then this.

[Strike For The South]

Locking him up is a waste of resources. There's also a risk he could escape. He can't if he's dead.
A 20 year old would be on average a great candidate for organ donation. The remnants that can't be reused can then be discarded.

Death is never "to good" for anyone. Especially when there are people who could actually use his organs for good.

You kill infants and it shouldn't be a question. Besides locking him up in the loony bin will only put the docile crazies at risk.