We may have a nearby brown dwarf. IIRC I think it was a theory to explain the movements of celestial objects (rocks) way out at the edge of the solar system. A brown dwarf could be hard to see but still effect the courses of space rocks. It wasn't hurtling towards us though. The Niburu thing goes back to Zacharia Sitchen's dodgy translations of ancient Sumerian texts (internet search "Sitchen is wrong" for another view on that) and the books he wrote weaving a huge ancient astronaut theory out of it. The thing you linked looks to be linking the two things together. I have no idea where the seven planets are from. I can't find anything on Ethan Trowbridge beyond a load of things about Nibiru being about to destroy us all. Also, Nibiru was supposed to be a lost extra planet in a long orbit rather than an entire solar system, so he's obviously just bolted a hot search name onto his story to get clicks.
I wouldn't worry too much. Another solar system flying through the solar system towards us should be glaringly obvious to even an amateur astronomer.
We are quite likely to be killed by a random space rock crashing into us with no warning though, as we are overdue and also the Yellowstone supervolcano is overdue an eruption and when it goes so do we...
So in summary I'm sure it's an attention grabbing hoax but we are all doomed anyway.
Edit: Reading more I see that this is all another explanation for climate change where it isn't the fault of big business, governments or us and all the actual science is a coverup. (Pretend there is a raised eyebrow and stroking beard emoticon here, as we don't have one) Who is trying to cover up what?
Stare not into the conspiracy, lest you become the conspiracy!