Trying to get in touch with his long lost brother?

Is that was stan was trying to do with his machine? Trying to get in touch with his long lost brother who is lost in space or an alternate universe or a parallel universe or something?

apparently Stan's machine is not exactly the same as the machine that the author of the journal said might destroy the world or the universe, since it hasn't yet. Although considering how high some objects floated before gravity was restored, I have to wonder if everyone in Gravity Falls has survived so far.

Didn't the shape shifter describe the author of the journal as six fingered? Didn't the man who came through the portal have five fingers and a thumb and look a lot like Stan?

Stan said the man from the portal was his brother. That could mean that he was his brother, or possibly a very close friend, or a clone, or himself from a different time, or an alternate universes eelf.

My tenitive theory is the man from the portal is the real Stanford Pines who disappeared from his car right before the driver less car crashed and thus was assumed dead even though thee was no body in the car, as Dipper and Mabel might have found out if they read more of hte newspaper article. I suppose that his rotten no-good brother blamed himself for the disappearance and has been trying for decades to get back in contact with the real Stanford Pines.

Apparently Mabel and Dipper's parents never heard about the reported death of Standford Pines and his brother never corrected them when they arranged for Dipper and Mabel to stay for the summer.

It is possible that somebody else was found dead in the crashed car but was burned beyond recognition, but that theory has sinister implications.