marithyme says:
I think she should be younger, and he's coming because she's written to you asking for your help. She didn't understand why he left all those years ago, and have no idea about your power.
What do you envision their relationship to be? Did they keep in contact? I imagine he'd feel protective of his little sister, but if he did write, she would have a highly-edited version of his shenanigans where he was always the victim/hero.
Do they acknowledge the fact that they're siblings 1) in public, or 2) in front of the party, or 3) in front of her warders? If Jandral is in hiding then acknowledging the relationship may give him away, unless those present don't know or don't care who the Kashyl family is anyway.
Maybe he needs to tell her she's a channeler. She doesn't know yet, does she?