Objectivetruth,
You ask what I attribute that brothers experience to. This may sound weird but, I believe that many JW's want to fit in with the crowd, the group dynamics, and they will attribute to "demons" that which is pretty normal, mundane experiences.
My friend who is still "in the truth", swears that the house that he was raised in with his sisters and aunt and uncle, was demonized and that he saw demon activity in the house. When I talked to his uncle, who is not in the "truth" and never was, he told me that it was all nonsense, no such things ever happened.
At one time, when I was a teenager, we began hearing a "hoo-hoo" sound off and on over a period of time. It sounded a lot like an owl, but there were no owls anywhere near where we lived. Of course my mom immediately declared it was a demon. Probably brought in by ME! I had just recently bought a new "WHO" album, Quadrophenia of I remember correctly. (hoo-hoo, The WHO).
Well, after a few days we found the demon. It was my brothers spider monkey. We never knew a monkey could sound so much like an owl!
And then there were just dozens, if not hundreds of stories that I heard from the brothers and sisters about the same things we hear so often, you know, trinkets bought at garage sales, second hand stores, etc. You know, "Something weird happened, must've been that knick-knack I bought at Goodwill", etc.
It just always seemed to me that ALL Witnesses just WANT to have their own DEMON story. They don't feel complete without one!