When Valjean first sees him, he doesn't know what to think or how to respond. He thought it was seeing things.
He was sitting in his small home reading a novel in the dim light of the room only illuminated by a candle burning beside him. In the corner of his vision, he sees something move—though he knows he lives alone, and pushes it aside. But there's a glowing to it, something out of place. And then he knows he's not alone.
Looking up from his book, he sees Javert. But he's different, translucent in a way, and he's glowing faintly like a lantern in the darkness. He's wearing the uniform he wore when he had jumped into the Seine, and holds that same sullen, troubled expression on his features. He almost looks lost. Valjean thinks he's most definitely seeing things and going insane when he sees wings spread out behind him, the feathers elegant and soft looking; finding himself tempted to reach out and touch them, but he holds back.
Javert is silent in the first long, confusing, agonizing moments that hangs between them; Valjean's book having been placed in his lap and his gaze fixed on the man in front of him. Javert was…an angel? Valjean believed in God, he believed in saints and Angels; heaven. But he never would have expected to have one standing right in his room, looking utterly lost and troubled.
And after a few moments, Javert turns and wanders—he's gone; leaving Valjean disoriented and concerned. He places his book on the small table next to him and gets up, stepping into the kitchen to see if the angel had wandered there, but he was nowhere to be found. Valjean took a deep breath and ran his fingers through his hair, muttering something to himself how he was seeing things, how he was getting too old; going to make himself a cup of tea to calm down and maybe he would even take a nap. He missed Cosette, but right now, he was content that she wasn't here to witness him…hallucinating. Was he hallucinating, he didn't know—but whatever it was, whatever had brought Javert, glowing and elegant appearing with his outstretched wings—he wanted it to happen again so he could at least speak up to see if he wasn't losing his mind.