What do you mean it doesn't and it won't?But it’s doesn’t and it won’t.
Alpha Centauri will be at it's closest to the Sun in 26'000 years time, give or take. It then starts moving away from the Sun, in pretty much the same shape orbit (and time frame) as it moved towards the Sun. Therefore, if it moved one light year closer to the Sun in 26'000 years, it will move away at the same rate.
In fact, in as little as 55'000 years, it will be just as far away as it is today.