Word had traveled along the angelic grapevine that things were bad, but Gabriel hadn't realised that they were this bad. Cas was gone, Dean was spiraling into alcoholism and depression, and Sam...Sam was in a really bad place. Not that you'd be able to tell just by looking at him. He still smiled and laughed and acted like regular old Sam; but Gabriel was an Archangel and he knew exactly what was going on in Sam's head. His telepathy let him see what Sam saw: Lucifer. At least, Sam's mental representation of Lucifer - the real Lucifer was still firmly locked away in his cage. This, surprisingly, was the bad news. If it had been the real Lucifer haunting Sam, Gabriel could have fixed the problem. He'd probably have created twenty additional problems in the process, but at least Sam would have no longer been crazy. However, since it wasn't the real Lucifer, Gabriel was at a loss. The human mind was complicated and messing with it was unlikely to end well. He was willing to try and pull Sam out of this Hell his mind had created, but he knew he was never going to get the opportunity as long as Dean said no to angelic intervention and Sam refused to tell him how bad things really were. The whole situation was ridiculously over-complicated, but Sam had asked (begged) him not to meddle until the Leviathans were stopped. There were a lot of good people that needed to be avenged, and Gabriel could teach them all the lessons he wanted when that was done. Normally, Gabriel would have ignored him; but he could see exactly how fragile Sam was. He was willing to respect his wishes, if only because doing otherwise might push him over the edge. He needed to be careful if he was going to put Sam back together. If he was going to put both of them back together.