Kill him
The former president was acting without lawful authority in assuming various powers to himself and incubating a dictatorship. He in fact committed the first offense against democracy and the rule of law. Though there are reasons to question the actions of the military (insofar as they have not immediately acted to restore the proper authority of the law), that the actions of the former president were a treason against the government is not a matter of dispute. The authority of government rests in its laws and institutions. A president who tramples on those institutions is betraying his duty to the law, the source of principled authority for government.
Treasons of this kind have resulted in appalling loss of life from misrule on the African continent. They are a uniquely injurious form of treachery. Here there is a unique opportunity to suitably punish an odious criminal in circumstances that leave no doubt as to his guilt (having declared himself to be this kind of traitor in various official pronouncements entitled to factual deference). I am greatly saddened for liberty that he is apparently "safe and well." Since he is presently in military custody I can still take some hope that he may yet be killed.