Na, that only applies to Muslims/believers who got haram money and knew it, ofc any haram money/businesses hes making now must be stopped and donated asap
"Whoever does something, not knowing that it is forbidden, then he finds out that it is forbidden, is not to be punished. If he engages in a riba-based transaction, believing it to be permissible, and he acquires wealth thereby, then an admonition comes to him from his Lord, he may keep his past gains. "
"So whosoever receives an admonition from his Lord and stops taking Riba (usury) may keep his past gains”
[al-Baqarah 2:275].
End quote from Tafseer Aayaat Ashkalat ‘ala Katheer min al-‘Ulama’ (2/578)
Those are for transactions in which both parties knew that it’s haram and have consent to one another.
Sex work is considered “evil money” in Islam not a transaction, similar to alcohol sales etc.
Therefore, it depends on whether the buyer knew exactly what they were paying for.