He watches the dog approach but stays where he sits, not bothering to make any movements. It's clear that Grey isn't an attack dog or else he would have been aggressive from the start, and those are the only animals the soldier ever has a problem with.

It's only when Diarmuid enters the room with the tray that he leans forward to accept it, looking down at the offered food for a moment and trying to recall when, if ever, he's been served a meal with the purpose of helping him feel better. But he can't remember, so he simply nods, setting the tray down before he takes the spoon in his right hand to begin eating. His left hand is best used with less delicate things than holding spoons and cups, so it rests at his side, mostly unused.