all this rolling out

[jacdac]

Sally smiles as she sees all this rolling out in the time she doesn’t have but they do. You must know this already, she wants to tell her daughters. But you’re so stubborn that the story will take time, years. That’s how stories are in life. It’s like reading the dictionary from cover to cover, she wishes she could tell them.
Source: The Grammarians by Cathleen Schine
Context: Sally is at death bed. all in she sees all refers to a story that is developing in her mind about the future of her two daughters and their families.

From the context, I assume rolling out could mean happening or taking place. But I could not find a definition that corroborates my assumption.
Could I say ‘I wonder how this will roll out‘ to mean ‘I wonder how this will play out’?

thank you.

 

[Uncle Jack]

From the context, I assume rolling out could mean happening or taking place.

I agree. It is not a common expression that I am aware of. roll - WordReference.com Dictionary of English has this definition:

42. roll out: unveil​

I don't think this situation is really what the dictionary definition refers to, but you might see how Sally could have come to use it. We do use "roll" in relation to time, though:

5. to elapse, pass, or move, as time (often fol. by on, away, or by).​

Could I say ‘I wonder how this will roll out‘ to mean ‘I wonder how this will play out’?

Yes, I think you can. She sees all this playing out in the time she doesn't have. I am a little unsure, because there might be meaning that has escaped me in the sentences that come before the first sentence. When a sentence you are asking about includes a pronoun ("this", here), it is generally better to quote the sentences that come before the one you are interested in, so we can see what the pronoun refers to.