I find this lacking as a theory.
Which star? Even if it was 20 ly way, we would know the star, if by nothing else than by infrared.
Barnard’s Star, the fastest moving star nearby isn’t even moving that fast.
He needs to find an name the star before this goes any further.
To do what they’re claiming, the relative speed of this star to the sun would have to be > 180,000 miles per hour. That’s hard to believe.
Barnard’s star is moving significantly faster - 140km/s vs. 80km/s relative to the sun.
Scholz’ star is *tiny.* The entire binary system is < .15 the sun’s mass. The apparent magnitude of the star when it was @ .85LY from the sun was still 20 times too dim to be seen by the naked eye.
The math definitely works out - Scholz’ star would be 18.6ly way if it was moving away from Sol @ 80km/s relative velocity.
The objects were too low-mass to have any significant impact on the Oort Cloud, much less the Solar System. The binary system would have likely gained +/- .25km/s on approach to the sun, only to lose it again on its way out.
Scholz's star is actually a binary system formed by a small red dwarf, with about 9% of the mass of the Sun, around which a much less bright and smaller brown dwarf orbits.