This was the period where they made John, Colleen Brady and Santo Dimera's son. So John and Kim were first cousins, making Theresa and Brady 2nd cousins.
Once Theresa showed up they had Hope deliver a message to Brady saying that John who was off screen, found evidence that he wasn't Colleen and Santo's son Ryan.
The whole Colleen and Santo thing was beyond ridiculous. It really was just a Sami/Ej vanity project from TPTB.
They should of just left John as Daphne's son. It explained his conception, his Alamain adoption, and why Stefano hated him.