Do you think Aeetes and Medea are supposed to be mortals or gods? Aeetes is directly said to be Circe's brother in the Odyssey, and Circe herself is said to be a goddess. Aeetes is son of Helios and an Oceanid, and Medea is daughter of Aeetes with another Oceanid. However, they never seemed to be treated much like gods in my impression. I know that the discussion nymphs being immortal or not is always difficult, but the fact that Aeetes' sister is explicitly a goddess is what confuses me a bit.
We know that family is not always indicative of someone's nature - just consider that Zeus has children by three of the Pleiades and only his son with Maia is a god - so it could go either way. It's definitely possible for them to be deities though. In Hesiod's Theogony (albeit in a part of the poem that probably doesn't belong to Hesiod himself) Medea is listed among the goddesses who bore offspring to mortal men:
„Now Olympian Muses, sweet-voiced daughters of Zeus the aegis-bearer, make the theme of your song the immortal goddesses who shared the beds of mortals and bore them children with divine looks. Radiant Demeter, a goddess, and Iasion, a hero, coupled with passion on a field plowed three times, in the rich soil of Crete; … Harmonia, daughter of golden Aphrodite, bore to Kadmos Ino and Semele and fair-cheeked Agaue; Autonoe, too, … and then, Polydoros—all in turret-crowned Thebes. Kallirhoe, Ocean’s daughter, spell-bound by golden Aphrodite, coupled in love with stout-hearted Chrysaor and bore a son surpassing all men in strength, Geryones, whom brawny Herakles slew in sea-stroked Erytheia, … To Tithonos Eos bore bronze-geared Memnon, king of the Ethiopians, and also lord Emathion. The blossom of her love for Kephalos was a splendid son, high-honored Phaethon, a man of godlike beauty; … Then Jason, through the decrees of the undying gods, took as his bride the daughter of Aietes, the Zeus-cherished king, after he had accomplished many grim labors on orders from Pelias, the great and brazen king, whose deeds were shameless folly. These done, Jason suffered no few hardshipsand then on a swift ship sailed to Iolkos, whence he brought a bright-eyed maiden who became his buxom wife. And Jason, shepherd of the people, made her submit to his passion, and she bore Medeios, a son fostered on the mountains by Philyra’s son, Cheiron, and great Zeus’s design was fulfilled. Then come the daughters of Nereus, old man of the sea: the exalted goddess Psamathe, incited by golden Aphrodite, lay with Aiakos in love and gave birth to Phokos; and then Thetis, the silver-sandaled goddess, became the wife of Peleus and bore lion-hearted Achilleus, breaker of men. Fair-wreathed Kythereia gave birth to Aineias, after she and the hero Anchises tenderly coupled on the wind-swept peaks of many-folded Ida. And Kirke, daughter of Helios Hyperionides, took as her lover Odysseus, whose resolve never flagged, and bore him Agrios and the blameless and stout Latinos, and also Telegonos, under the spell of golden Aphrodite. … Kalypso, the radiant goddess, came to know the charm of Odysseus’s love, and bore him Nausithoos and Nausinoos. These are the immortal goddesses who shared the beds of mortal men and gave them godlike children. But now, O sweet-singing Olympian Muses, daughters of aegis-bearing Zeus, sing of mortal women.”
There are also sources where she resembles a mortal woman far more than a goddess, so it's hard to say anything for sure. I guess she could be some sort of deity anyway, only one of lesser power than the likes of Aphrodite, Hera, Hekate or Demeter which would be why she can be manipulated by them or needs to defer to them in various accounts. Even less sure about her father, but he might be in a similar position.
