I think they do. I mentioned it in another fic I wrote, but basically I feel like if Matthew is Simba, and Isaac is Mufasa, then Flint is definitely Zazu (because the way Flint was sent to watch over Matthew was highly reminiscent of The Lion King for me). Unbeknownst to Matthew, during the time before the Grave Eclipse Flint secretly reported back to Isaac, letting Isaac know how his son was faring. I think Djinn are the messenger pigeons of Adepts, therefore; because they can travel rather quickly, and because they can talk, they're used to pass messages rather than writing out lengthy letters (I feel like this is partially supported by how Pewter went to go fetch the kids for Laurel). However, when the Grave Eclipse spread, it cut off Djinni communication; Flint could no longer travel easily through it like he could before, because the darkness was too strong. This sent off warning bells to Isaac, but unfortunately, he could not leave his post at Mt. Aleph to go look. Of course, Kraden could always still send letters, but that form of communication is increasingly slow, though reliable.
In any case, Jenna is the one who ultimately goes to look, because . . . well, that's in the fic, haha. It'd be even more TL;DR to explain it here.