(fallen london stamps by an odd habit of the good doctor's: he tends to touch his close friends a lot, unless they don't want to be touched. so, if you're close to him, and amenable to it, he might do stuff like lightly grip your shoulders with the tips of his fingers, or cheerfully tap you under your chin if you're taller than him, or pat your head if you're shorter
or, if the two of you are deep in a conversation, he might reach over and gently take one of your hands, and hold it enclosed in both of his - one below, and one above.
it's almost as if he's reminding himself that you're real. that you're still there.
I think despite this, he's not much of a hugger. not because he dislikes them, more that he doesn't actively crave them and tends to forget they exist. he's much more of a hands person
(being little a full-body-squoze by a close friend does help him when his nightmares get dangerously high, though)
actually I take that back. I think hugging doesn't help when his nightmares are bad. I think, given that his hold on reality gets tenuous and his nightmares sometimes involve being dragged down and buried by the dead, they might make things worse
nothing much to do about his nightmares but to try and get him to lay off the Correspondence and suchlike before they get too bad, and wait for things to blow over if they end up getting bad anyway