Not a pharmacist but ex avid drug taker - the only stimulant that would be super intense then wear off that quickly, causing a crash would be......crack. Maybe hunter's helping the big guy out. Adderall, Vyvanse, provigil would all last way longer. Meth would really have been the best choice as it would have vice gripped him into being alert but likely would have reduced coherence. And as for snorting coke, while he'd probably want more, wouldn't need more that soon aka a comedown wouldnt set in that quickly.
But that's why I don't think uppers make sense with Joe. He's obv not sucking glass dick before a debate. I really think it's purely a stamina issue. He can't focus for as long as the debate required. I think he fought as hard as he could in the first half and by the second he just couldn't keep going. It's sad.
Lots of prayers for your family fellow pede xx