Lions catatonia isnt what you think... (spoilers)
...at least, it’s not what many threads on here seem to suggest. He is NOT in a ‘stupor’ in the end, he is unconscious.
He is lying unconscious because they had to sedate him. The doctor says this. Lion is all strapped up, showing that he must have been flailing about, probably yelling nonsense about “Long John” and “I’m going to fight ‘em!” So, he was all strapped up, plus they had to sedate him.
Catatonia often manifests itself as this type of crazy wildness, instead of the commonly imagined ‘stupor’, although the two extremes are similar in being non-responsive. He was probably diagnosed with schizophrenia, triggered by a nervous breakdown. It takes a long time to recover from, and given that treatment was so poor back then, he’d probably have mental instability issues for the rest of his life.
His nervous breakdown doesn’t seem at all unreasonable given his character and the plot, and I don’t see how it’s a cop-out. We saw signs that he was depressed after the rape, developing a drinking problem (rubbing his hands and saying “I could use a drink”), with his life philosophy turned upside-down (very confused by Max’s striptease), and then the vindictive evilness of Annie burst his last bubble. The crows got the best of him. He’s clearly slipping away during the whole fountain scene, then totally losing it and becoming delusional. It’s a touching ending when we see Max spend his precious extra $ for a round-trip ticket, against his calculated plans. Lion has nobody in the world, but Max wants to come back and take care of him. His self-sacrificing caring for Lion is opposite of what he professed at the beginning (“the meanest sonnofabitch” who “doesn’t love anybody”).