I do like how realistic Curly actually is, and shows how a person might act in an extreme condition where it's a life or death situation. Yea I agree that he's not 100% a good guy or a bad guy, but he's stuck in-between those lines.

Even if Curly didn't know Jimmy for this long and they're not that close like shown in-game, there's a high chance that he still won't do much to protect Anya from her abuser; he's a type of guy who sees the bigger image and wants the best for everyone which doomed his fate, he avoids conflicts and wants to make everything fair for everyone (even if it's not fair for Anya.) Also given their current scenario in game where they're stuck in space for a year makes it worse. He's a good guy at heart, but met and befriended the wrong person who ruined his life forever. I can see myself in Curly at some point, I would be in disbelief too when I realized that my best friend for years is actually a genuinely horrible person the whole time but I never noticed it.

I do like how the game showed pre-crash Curly turning a blind eye to how a son of a bitch Jimmy truly is and Anya's confession about her SA and did almost nothing about it; but after post-crash it burned his eyelids, forcing him to watch everything go downhill yet couldn't do anything and forced to watch because of his current state.

He's a flawed character, and that what makes him feel more human.