[Cain thinks it's good to get used to such things, since people are going to say what they will, so he just nods.] It can be a bit more complicated than that. He might want to be alone sometimes, but it doesn't mean he wants to be alone...
I suppose what I mean is, if that fails, you can let him know he can call you if he needs company and give him some space. Combat can damage the mind in strange ways, sometimes.