He thought it was good to see him. Mason rarely had reason to feel relief or hope. He'd grown bitter from watching people around him be happy, in love, blah, blah, blah, and had stopped looking for that for himself. He'd been caught off guard by Archie, which was why at this moment he felt a surge of relief, and not just for himself. After watching over Archie's sleeping form for days Mason was relieved to see him awake.
Usually a man of self-restraint, this time Mason didn't stop himself from moving forward to draw Archie into a hug.