Is forgiveness granted to one who was righteous then returned to sin, and is there repentance for him after repeatedly committing the sin?

We advise this person to renew his repentance and not despair of Allah's mercy, for Satan wants the believer to tire of seeking forgiveness. This brother should have a good opinion of his Lord, perform the obligatory and supererogatory acts of worship, increase in effacing good deeds, and repent sincerely from the sin, for "the one who repents from sin is like one who has no sin." If he returns to the sin, let him return to repentance and not tire, for Allah forgives him what he seeks forgiveness for, and accepts his repentance whenever he turns to Him in repentance. Let him strive to correct his repentance by resolving not to return to the sin, and regretting having committed it. If he happens to return to the sin, he will not be held accountable for the sin from which he repented, and no matter how many times he returns (to sin), let him repent until Allah blesses him with a complete cessation of this sin.