Panel 1: As he eats supper, Liz reacts to the horror that is John having an interest that gets in Elly's way by asking what's up with him. Mike dunno.
Panel 2: Mike does know that Elly said John has entered his second childhood.
This is, of course, because Lynn no longer loves an outside interest that leads Rod out into the world and away from her stifling control.
Panel 3: Liz says that no, he hasn't. Mike asks her how she can tell.
Panel 4: We get hating Rod's hobbies in hating her children's refusal to eat her terrible cooking when Liz says that John still eats his peas.
Summary: As I've said before, Elly never quite understood that being an adult didn't mean jettisoning the ability to enjoy things. This is because her creator is equally transfixed by the delusion that adulting means frowning and worrying all the damned time.