All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.
Committing a grave major sin is evil, and publicizing it is another sin. It is confirmed that the Prophet said: “All my nation is pardoned except those who openly expose their sins (publicize them).” [Al-Bukhari and Muslim]
Therefore, if this person has openly publicized his sin after he repented had from it, then this contradicts the essence of repentance because one of its conditions is to regret and feel remorse for having committed the sin.
Hence, this person must repent from having exposed his sins and renew his repentance from the sin that he had committed. He should know that no matter how great the sin is, repentance wipes it out – Allah willing.
No matter how many sins a person had committed and how much he exposed his sins, once he sincerely repents, it is as if he did not sin. The Prophet said: “The person who repents from sin is like the one who has no sin.” [Ibn Maajah]
If repentance wipes out the sin of Kufr (disbelief), then it is with greater reason that it wipes out sins of lesser degree than Kufr, even if the matter is exposing one’s sins. Allah Says (what means): {Say, “O My servants who have transgressed against themselves [by sinning], do not despair of the mercy of Allah. Indeed, Allah forgives all sins. Indeed, it is He who is the Forgiving, the Merciful.”} [Quran 39:53]
For more benefit, please refer to Fataawa 382120, 369397, 256084, 360028, and 336685.
Allah knows best.