Your friend does not need to be re-baptized. There is only one baptism and no such thing as a re-baptism. The sacrament is greater than the worth of the sinful celebrant. Think about this: priests are human and indeed quite capable of sin. Each Sunday that they commune their faithful, no doubt some are living in sin. But the Body and Blood of our Lord is still effectual. The priest will have to give answer before the Lord some day and meanwhile your friend can relax and depend upon the fact that she is most certainly a baptized child of God.