Summary: its junk.
Other people have different opinions, but they are wrong.
If you're reading on past this point, I'll assume you don't care about me spoiling the surprise, not that there is any, so I won't take any care to hide the plot.
The worst thing about this is that its not total junk; there are some interesting ideas in there. But the ideas are badly handled, indeed the whole book is profligate with its miracles. If you're writing Fantasy, then every Elven kingdom can have its own magic, and the more the better. If you're trying to write "hard SF" as this guy is, then the game is to wring as much interest out of as few violations of the known laws as possible. Not to randomly splatter the book with new implausibilities, just because your poor tired imagination has run out of interesting consequences for what you've made up so far.
The sort-of basic premise is moderately interesting: what might a colony on a tidally-locked planet of a red dwarf be like? Unfortunately, the book totally stuffs up even trying to explore it.
Firstly, and utterly bizarrely, the mega-expensive task of colonising is shambolically amateurish: the colonists are a bunch of ex-cons. This is utterly implausible; who would spend such a vast amount of money on colonisation, then set it up to fail? I guess he is harking back to British colonisation of Australia; but if so, it doesn't work. His colonists get no training at all; they are deliberately spread out over the planet in small groups. Then, the astronauts that took them all the way to Alpha Centauri go back to Earth. That is so mind-bogglingly fuck-witted that its hard to believe even a sci-fi author would do it.
Secondly (and here the profigacy starts to come in) although his characters have (correctly) made much of the stability of red dwarfs, no sooner do his people turn up than the sun turns variable and it starts to get cold. Aie, its so stupid. Not only that, but that level of variation would have been visible from Earth, so we'd know about it. His characters then start migrating across the planet, but in a very uninteresting way, they might just as well have been in a Little House on the Prairie not on a tidally locked planet.
A bit later it turns out that there's a Mysterious Alien Artifact on the planet which just happens to be some kind of hyperspace gateway (but a lightspeed one, ho ho, pretending to keep his credentials intact) back into the solar system. At which point, not one of his characters turns to any one of the others and says to themselves "fuck me, but that's a bit of a co-incidence isn't it? Humans happen to have gone to precisely one extra-solar planet, and that planet just happens to have a gateway back to the solar system".
Meanwhile, back in the solar system, amongst some tedious badly imagined politics, one of the other characters goes into the gateway there and (this bit wasn't well described) emerges with a twin. And suddenly her entire life has been re-written backwards in everyone's memory so that this has always been so. Everywhere but in her own mind. Oh, and on her mothers gravestone, which mysteriously gets forgotten to be re-written. The book provides no explanation for why this twinning might be done (much less of an explanation of how the re-writing might be done), and nothing interesting happens as a consequence, so it is not just profligate, but pointless mindless profligacy.
Meanwhile, in yet more profigacy, a sort of light-sail AI is also sent to Proxima, but does nothing interesting when it gets there; it just hides around the far side. Where yet another fucking expedition from Earth, this time a solo one, has died quietly in the wilderness. Its all so mind-bogglingly badly thought out I just can't bear to write any more.