Scene 1 from the movie Little Miss Sunshine
Richard: And how Dwayne's utilizing seven of them in his personal quest to self-fulfillment.
Sheryl: Richard, please.
Richard: Well, I'm just saying I've come around. I think he could use our support.
Olive: How did it happen?
Frank: How did what happen?
Olive: Your accident.
Scene 2 from The Matrix
Morpheus: I imagine that right now, you're feeling a bit like Alice. Hmm? Tumbling down the rabbit hole?
Neo: You could say that.
Morpheus: I see it in your eyes. You have the look of a man who accepts what he sees because he is expecting to wake up. Ironically, that's not far from the truth. Do you believe in fate, Neo?
Scene 3 from The Matrix Reloaded
Morpheus: Neo, if you're out there I could use some help.
My best guess is that the first could signals a suggestion or offer, the second giving permission and the third expressing strong feelings (conditional).
Please help to explain the different usages of could here.