I think more than 25 years of actual prison time starts to get pretty harsh given that central bankers have been more or less defrauding the public for the past 100+ years. Bare minimum 20 and he needs to repay as much as possible.
Part of me respects the bastard because he just looked at a corrupt system and thought if these fuckers can get away with it why shouldn't I be able to? But don't hurt the little guy in the process obviously.