According to wrestling news sites, Shane McMahon appeared to be legitimately injured. He was speared up high during a match and fell, hitting his head on the mat. Some sites indicate that he was knocked unconscious. Although he appears to have been injured, it's not a serious injury after all.
The WWE’s silence also speaks volumes. In a case where a superstar’s injury is fake, the WWE will often continue the charade on social media and on their website, giving updates about how the performer is supposedly doing. On the other hand, when there’s a real injury, the company usually remains completely silent while they figure things out. After SummerSlam, for instance, there was no official word about the extent of Finn Balor’s injuries until shortly before Raw the following night. After Survivor Series, Shane McMahon presumably had to undergo some concussion tests.
Many fans who were in attendance for Survivor Series have since provided their perspective on social media, saying that it seemed clear to those in the room that Shane was definitely hurt.
The likelihood of McMahon's injury being real (or as serious as claimed) is somewhat hard to believe due to the WWE's tendency to stage and dramatize their fights. The nature of the show is to be ongoing, suspenseful entertainment for viewers. It is unlikely that they would allow one of their fighters to be seriously injured during a performance.
Shane McMahon is a wrestler with the WWE. It is the opinion of myself as well as many others that the WWE fighting is primarily fake. The injuries these wrestlers sustain are planned for entertainment purposes. The fights are theatrically created for television viewership. Therefore, the injuries that Shane McMahon suffered at 'Survivor Series' were planned for television and were not real.