Jace's mom. Jace being in Israel would really have the potential to fuck things up for anyone involved with him in the last 6 months. Anything happened to Jace then people will wonder how a schizophrenic man managed to even get that far with his plan. His online footprint will be followed up, the media will see how people online had quite a bit of influence over him, and next thing you know they'll be claiming that online bullies talked Jace into flying to Israel just to get killed. Gail and Rob would suffer as they get questions like "How did you let this happen? Why didn't you monitor him?".
Eli and Tyce are morons for the most part but they don't have the delusion of being the embodiment of all things American, they don't feel the need to prove themselves to the world, they're.. well, they're just more blatantly self-serving. Jace cares about fame, having people want to be his fans and friends. Tyce and Eli just want pot, money, and video games. Jace has those things.