I like this witness, and she definitely knows what she's talking about in terms of all the various forms of abuse. I am really eager to hear how she relates this to Travis and Jodi. I would be surprised if she makes a flat out conclusion that Travis was an abuser -- maybe she'll couch it as Travis having more power in the relationship and Jodi's perception. A lot of what she will be relying on will be what Jodi has relayed to her, but there are other pieces of evidence besides Jodi's word that she can point to as well.
For example, Travis not wanting Jodi to spend time at Rachel's, Travis joking about why Jodi would want to spend time with her family, telling her not to write things in her journal, the names Travis called her and ultimately telling her she's the worst thing that ever happened to her, Travis getting mad at her for hanging out with John "*advertiser censored*" because he was not in the church, etc. Those are all things that can be found in her journals or in the text messages between Travis and Jodi.
And I hate to say it, but those behaviors of Travis' are unhealthy behaviors and are not appropriate in a romantic relationship. Obviously, the healthy thing to do would be for Travis to leave the relationship if he was unhappy with Jodi's behaviors. Travis did have more power in the relationship, but that does not mean he was abusive -- especially in this situation because Jodi was constantly doing the passive aggressive stuff to hurt Travis and sabotage his life.
I'm not particularly worried because there are so many behaviors of Jodi's that Juan can ask her about that clearly fall within her continuum. And besides that, there's nothing that remotely would cause Jodi to fear for her life when she murdered Travis.