Longer answer: The sentiment expressed is one of (attempted) healing, and if nothing else, of preparing for the inevitable with the best possible forethought. I've read often (even in these hallowed electron stores) of regrets expressed because You Didn't Have Time/Opportunity/Forethought/Inkling of Impending Death/ to say one's final goodbyes (or at least, to make some contact before the final goodbyes). This letter is a gentle admonition to her (and to the rest of us) that while time may be infinite, our slice of it in this life is not, and neither is the slice that belongs to loved (or even formerly loved) ones.

She needs to make peace, as much as possible, with her past, so that she does not add to the store of regrets when her father finally passes.

You done good, Rand....