The man died in 1988, while in exile, so no criminal charges were filed against him. It was amended in 1993 by RA 7659 to include other participants and define aggravating and mitigating circumstances. Under the law, reclusion perpetua means imprisonment of 20 to 40 years.
Voluntary surrender coupled with admission of guilt and illness can lighten the penalty.
Habitual delinquency aggravates it. However, I think that the law on plunder has not been carefully studied. It is too small by foreign standards. Aside from that, there was an anti-Marcos sentiment at the time when the law was passed. Congress was headed and composed of anti-Marcos people and its leadership consisted of victims, if not enemies of Marcos.