I think you can take Dr Steven Greer with a grain or two of salt.He`s been around for many years with his UFO exposures one dealing with a miniature alien.
And a couple of years ago their was to be according to him a worldwide exposure /disclosure of Alien life in the Universe
So far it hasnt occured ( think Armageddon being just around the corner )
Personally I think he`s just another guy cashing in on the peoples belief in other world civilizations .
For the record I personally do not think we are the only life forms in the Universe however I dont make money out of promoting that personal belief.
A lot of his followers have alien watchers where they go out in small groups in the countryside and meditate and chant and then have these "experiences" of cold feelings "aliens fleetingly off in the distance and breezes of the wind.,lights in the sky and so forth.
I have a close relative who led some of these excursions and doesnt do so now.
Make that out of what you will