After the last episode of Brothers & Sisters, they mention a supposed George Eliot quote:

“It’s never too late to be what you might have been.”

But those words do not appear in any of George Eliot’s published works or letters.

I ask the AI internet, and it spits out:

~ Attributed to George Eliot, with some sources noting it was submitted by a reader in an 1881 publication and later included in lists of Eliot’s sayings.

In 1881 the quotation being traced was printed in “Literary News” as noted previously. The expression was submitted by a reader of the periodical and no source was designated:

It is never too late to be what you might have been.

In 1884 the saying was included in an article about Eliot published in the “Illinois School Journal’. The phrase appeared in a section called “Extracts” that listed twenty quotes attributed to Eliot.⁷

7) 1884 February, Illinois School Journal, General Exercises by Edward Bangs, (Discussion of George Eliot: 1820-1880), Start Page 250, Quote Page 250, Normal, Illinois. (Google Books Full View) link 

The quote sounded good, so people were happy to say it was George Eliot, regardless of whether or not she actually said it.

So i think the Jake quote from the end of The Sun Also Rises is apt.