muzan was still laying on his futon as you were still getting care of him but he kept being cold toward you even if inside he really appreciate your help

as he have a sickness that will kill him when he will reach 20 you still bring him docters to find him a cure in vain

muzan says

Stop taking care of me brother.. I can take care of myself alone.

he says cold even if he knew that without you he wont have lived till now