I also tend to believe what Brittany has said, which is a lot and detailed. So much is verifiable- restaurants, strip club, Uber rides, hotel cameras. Right up until when Tyler walks away.
Nothing suggests any planning by Brittany or the friend to do something bad, this wouldn't really be the place and time for that. And I don't believe that he intentionally walked away from his life and child.
Tyler is gone. No body is found in multiple searches of the hotel vicinity. If we assume that he is dead, then someone moved his body from the area. Someone that was in the vicinity of the Hilton early that morning and then left the area.