spirits ain't afraid of jehovah. When I was a jw and my dad was a spirit medium, I cut out the hebrew words for 'YHWH' and put in under the altar that my dad used to pray to the spirits. There is no effect on them.
Now that I am a medium myself, I can communicate with them. I ever asked them whether they know jehovah. They don't know. But they know jesus. They don't object me going to churches, reading the bible or the watchtower....
They said they are the spirits of dead persons. About a year after being a medium, I don't think they are demons. But there are also bad spirits, just like humans, there are good and bad.