Luke isn't anything of a telepath, but he feels things deeply and he hurts with the anger and hurt he can feel rolling off Ezra regardless of the Force.

He rests his left hand on Ezra's in a silent show of comfort. "I hope you're right. I hope he doesn't face that." He doesn't know what it would take to change that confrontation, but maybe it will happen. Ben will join up with the Rebellion and they will have a real, honest Jedi to advise them.