well, this suspect is dumber than the average, run-of-the-mill Taliban member.
Based on the charge document:
a) if he purposefully mailed non-functional "bombs", but still included the 4 parts that allow the FBI to classify it as a bomb (trigger, charge, power supply, detonator), he still gets the full treatment of Title 18 (as an "IED", instead of just "unmailable material" or "mailing a threat to the President", which is what ricin and anthrax senders have in common with lithium battery mailers and carries 5 to 10 years). If he'd just, for instance, mailed a stick of C4 and a pocketwatch, the same effect happens ("BOMB SCARE!!") but he doesn't go away for "IED"s.
b) if he did expect it to go off, then he's dumb because even (literal) uneducated and illiterate goat-herders can figure out how to make explosives go boom when you want them to
c) if he did everything with knowledge that someone high up would take care of him later, he's too dumb to know that any out-of-the-ordinary monetary transfer going to him, his family or any known associates will be flagged for the rest of their lives and grounds for conspiracy later on.
Edit: Though if some of the reporting is real, and there was only inert "explosive material", then I don't think he can be convicted, based on the charge sheet. He's back to "mailing threats".