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, sallallahu ‘alayhi wa sallam, is His slave and Messenger.
Firstly, you stated that this man signed the government papers without knowing that signing these papers is a divorce. If this is the case, then divorce did not take place because the husband did not intend to divorce, which is a fundamental pillar of divorce. An-Nawawi while listing the pillars of divorce, said, "The husband's intention to divorce: he must have the intention of issuing a divorce when pronouncing the words of divorce. It is not sufficient to intend uttering the words of divorce without intending the meaning of divorce." [Rawdhat At-Taalibeen]
It should be noted that the Muslim must not sign any paper without first knowing its content in order to avoid potential regret.
Moreover, divorce does not take place if he answers 'No' when someone asks him whether he is married or not, even if he intends to issue a divorce with this negation. The Shaafi‘i scholar Zakariyya Al-Ansaari said, "If a married man is asked whether he has a wife or not and he answers 'no', divorce does not take place because it is a plain lie (since he does have a wife)."
It is allowable to resort to Tawriyah (indirect speech or deliberate ambiguity, namely, to say something which has more than one meaning and intending a meaning different from what the listener is likely to understand) in case of a valid need, and it is disliked when done for no need. An-Nawawi said:
"The scholars said, 'If it is needed to serve some legitimate benefit that outweighs the concern of misleading the person to whom you are speaking, or it is needed for a reason that cannot be achieved without lying, then there is nothing wrong with using deliberate ambiguity as an acceptable alternative. However, if there is no interest to be served and no need, then it is disliked, yet it is not impermissible unless it leads to taking something wrongfully or depriving someone of their rights, then it is prohibited in that case. This is the guideline in this matter.'" [Al-Athkaar]
Allah knows best.