Yeah, 'How I Became a Sick Nobleman' does dig into that, but maybe not in the way you'd expect from a typical fantasy isekai. The protagonist's chronic illness isn't just a quirky character trait or a setup for a sudden cheat skill—it's the central lens for viewing the nobility. It forces him to navigate a world of politics, etiquette, and family duty from a position of perceived physical weakness. The story spends a lot of time on the sheer logistical burden of his status: the constant need for attendants, the restricted diet, the inability to participate in traditional 'noble' activities like hunting or swordsmanship. His struggle is less about battlefield glory and more about managing his household, reading political currents from his sickbed, and using his modern-world knowledge in very careful, calculated ways that won't overtax his body.
I found the depiction of his family dynamic particularly sharp. There's this undercurrent of pity, obligation, and sometimes outright dismissal from other nobles, including his own relatives. His value is constantly being reassessed based on his health that day. It turns the classic noble power fantasy on its head—instead of conquering, he's constantly negotiating for basic respect and a secure place within a system not designed for someone like him. The tension comes from watching him use his mind to compensate, turning his sickroom into a command center.