How can a girl who repented of a sin for years, then relapsed spiritually and religiously after her family learned of the sin and punished her for it, be advised and guided?

The girl's father and family should not punish or abuse her after her repentance. The friend should be reminded that swift punishment in this world is an indication of God's desire for good for His servant and His love for him, and that trials elevate ranks and expiate sins. Everything that afflicts a believer in terms of trials is good for him, as Allah Almighty says: "And perhaps you dislike a thing and it is good for you." The means of strengthening faith, achieving righteousness, and repentance have been previously explained in earlier fatwas.