What is the meaning of "May Allah Almighty curse him" and "expelled from His mercy," and can one who repents from the polytheism of sacrificing return to Allah's mercy?

The meaning of "may Allah curse him" is to distance him and expel him from His mercy, for "la'n" (cursing) in the Arabic language means distancing and expelling from goodness. Sacrificing to other than Allah is major shirk (polytheism) that expels one from the fold of Islam. However, whoever repents from sins, including shirk, Allah accepts his repentance, for Allah accepts the repentance of His servants and forgives all sins. "The one who repents from a sin is like one who has no sin."