I know, I got my equivalent of study leave today, the school found a way past the government ban.
Remember, Shaben has gone with them on his own accord.
Out of game I can tell you he won't be mistreated and that if you attack not only will your attack fail but you will be almost instantly slain.
The best way to help him is to tell the Council of Six about Lantan going to war and then follow up leads to find him, it is part of the plot to find him by the way.
The best course of action is exactly what Hammer is doing with Rex, maybe he could stop you guys attacking if you decide to do so.