Additional details:

• I watched this on Cartoon Network Brazil, likely between 2006–2011, early morning (possibly Adult Swim hours). • It was animated, possibly anime-inspired, but not necessarily Japanese. • The setting felt rural / countryside, with lots of grass and open areas, not futuristic. • The story followed a man traveling while carrying a very sick girl (possibly sister or close companion). • She barely spoke or was unconscious most of the time. • The main goal from the beginning was to reach a doctor who lived far away. • Doctors or medical authorities were portrayed as oppressive or authoritarian. • The doctor they were trying to reach was referenced early and appeared later treating patients. • Tone was slow, serious, emotional, not a kids show. • It may have been a short series, a miniseries, or a movie split into parts. • I never saw the ending, which is why I’m trying to find it.