Sadly, this isn't for his real crime of overthrowing Fiji's democracy (he wrote himself an amnesty clause in his unilaterally-imposed constitution for that). Instead its for a minor incident later, where he perverted the course of justice by investigation into financial mismanagement at the University of the South Pacific. The habits built up as a military leader and a dictator - of authoritarian command, and protecting his cronies while punishing his enemies - turned out to be illegal. And when democracy was finally restored with the 2022 election, and he could no longer lean on the police and judges, he finally faced justice.
Its like Al Capone going to jail for tax evasion. But its good enough. And maybe now Fiji will be able to overturn his self-serving "amnesty" and prosecute him for his real crimes.