I think a sickly Drakensis would almost certainly be euthanized. Although I suppose it's not impossible that their biological parents might take pity on them and arrange for them to be spared. It sounds like something Kobold might do.The best way we could adapt it is if it'll be told in Shounen style with a sickly Drakensis as a protagonist. The revelations of the world will be done akin to Attack on Titan's worldbuilding, contributing to the deconstruction of what makes a "penultimate man and society". Space planes and orbiting warheads would be the things that would replace the mechas.
I always wondered about the relationship the Drakensis had with their biological parents. Do they try to keep in touch? Do the Drakensis with the Polemarch's DNA get preferential treatment? What do they do for Father's Day and Mother's Day or do such holidays not exist in Drakia?