Morality should be included in all economic discussions. By pure economic standards, we would just kill all prisoners who get a life sentence. Incurable disease? Kill the patient. Disabled child requiring lifetime care? Kill the child. Slavery? Sure!
I'd prefer to address this via ethics rather than morality.
For most of my life, I supported capital punishment. I still have no moral objection to the death penalty in some very particular situations. At heart, I still think it's more compassionate for both the prisoner and the public to execute those who would otherwise be held without liberty for their entire remaining life. You know why I support LWOP? Because it actually costs less than the various options the US uses for execution. That's the only reason.
Incurable diseases that can be effectively managed are certainly no reason to euthanize the patient - but terminal disease, especially ones that cause either immense pain or significant cognitive deterioration? Those I 100% support a person's right to choose to end their own life with support and compassion. I think it's an absolute travesty that we treat our pets with more care and dignity than we do humans.
For most situations, parents are happy enough to care for a severely disabled child. But there may also be instances where an infant is so disabled that they won't have any meaningful quality of life, and requiring that their parents must suffer twofold seems to lack compassion. It's certainly not something I would support being used with abandon, but I also don't think it should always be disallowed. I'd prefer that such decisions be made prior to birth whenever possible. Consequently, that means allowing for medically justified terminations of pregnancy after viability, which I fully support.
Slavery? I suppose no post is complete without a leap into absurdity, so I guess I shouldn't be surprised.