Theta-gama sync is a brain state where you can start seeing the other side while you still awake! You pass by it before falling a sleep and upon waking up but you can reach it with meditation too.
This might help you!
Yes! We use TGS state for evocation! And you already stated that you invited him to you so he showed up once you held the TGS!
Keep in mind anytime you think about a spirit and ask questions in your mind you are making some kind of contact and basically interrogating that spirit! You might get answers in your mind that doesn’t sound like your thoughts and that is a kind of spirit communication!