Erik would have minded being called for exactly as much as he would have minded waking up to discover someone had left a pile of money in his room, so there was that. But either way it wasn't as if he were purposely avoiding Charles; it was better being in the same room with him even if for most of the last twenty four hours he'd been either silently apoplectic or wearing himself down enough to sleep. Charles was his touchstone, the only familiar thing in a world that seemed to have inverted itself specifically for the reason of shooting Erik in the chest.
His experiences with feeling as though the world should have stopped when it continues to turn on its merciless axis are many, and he doesn't try to pretend he doesn't feel this one. It doesn't mean that the world doesn't keep moving, though, and so he moves with it--he adapts. This means talking to Raven, it means parting his hair exactly as he would do on any other day, and now it means looking in on Charles, moving with a silence he doesn't try to correct when it's immaterial.
"You're drinking," he ascertains from the doorway; it's neither accusatory nor overly concerned, at least not yet. If he were going to be concerned he'd have to accept some of that turned back at him, and he refuses, as much as possible. Instead he sits down on the edge of the bed by Charles' knees, in space that speaks to familiarity and closeness, but doesn't touch.