There aren't any habitable planets in the Pleiades (Seven Sisters) star cluster.
Most of the stars in that system have only gone through their life cycle long enough to form an accretion disk of dust around themselves.....which, may in another few hundred million years possibly form into a planet....then it has to be habitable.
There is one system with proto-planets (asteroid sized) there in the Pleiades, but those bits of rock are a long way from forming into a life bearing planetoid!
They are all pretty young stars really, compared to ours - Sol, which is quite an old star.

So drake's supposition that Pleiadeian's exist....well, whole idea seems a bit raggy to me really.
If he's basing it on channeled info....that comes from familiar spirits, that are FAMILIAR with the lives of the people (poor suckers) they are giving info to....that kind of data is consistently unreliable.