This is my off the wall theory that I maybe believe like 15% so I'll see if anyone likes any parts of it.  First we all have tried to guess what that meant when the blood on the wall said he is mar or he is man but they were in Mexico and maybe the hooker wrote it and a close Mexican word to that is Hermano meaning brother so what if when Kirkland asked Red Johns friend in the hospital if he recognized him why ask that then kill him maybe Red John is related to Kirkland and he wants to maybe protect him or stop him now this brother theory could work for any of the other suspects so please help me out on this but the Hermano thing could be something just throwing that crazy way out there have fun with it.