Technically, he's (https://modernfamily.fandom.com/wiki/Joe_Pritchett) their half-brother but still, there was even an episode (https://modernfamily.fandom.com/wiki/Written_in_the_Stars) where Joe (https://screenrant.com/modern-family-joe-cutest-moments/) had a crush (https://www.reddit.com/r/Modern_Family/comments/ejc8s7/stuff_i_noticed_that_seemed_to_hint_at_joe_having/) on Claire and not one time, someone said (https://www.reddit.com/r/Modern_Family/comments/tgx2s9/are_we_as_a_society_going_to_forget_that_joe_had/) “hey that’s your sister (https://www.reddit.com/r/Modern_Family/comments/i8qghv/why_dont_claire_and_phil_remind_joe_that_claire/)!”