The situation indicates that: They are trying to look like they are interested, while they are actually in a stupor of daydreaming.
tilted head and a faint is a sign that their brain is not currently in an active use, usually caused by boredom.
Hand holding up a chin maybe considered as a form that displayed if someone is in deep thought, but if combined with tilted head, and freeze smile,
it actually indicate that they're just holding the chin so it wouldn't fall when they fall asleep.
