How are any of those groups "in charge" of the religion of Islam?
If they aren't, who is? They are killing, raping, and destroying in the name of islam and none of the "normal" muslims are stopping them, so I would say that they are in control.
How does any of that imply that ISIS "controls" say, my Muslim neighbor?
I said they control the religion, not your neighbor. If you neighbor doesn't agree with them he may disappear one day. I suggest that he watch his back.
Who is it that you think is going to come after him?
ask him, I am sure he knows.
I'm pretty sure that he's not living in fear, as you imagine.
You made the comment, are you going to back out of it now?