were you planning to repair the areas that are coming apart? or finishing it up - backing/batting/quilting?
or trying to sell it -as is-?
location matters and so does the venue-
around here- as is you may get $5-$10 for it-
repaired and finished you may get $100+ but it takes the right person at the right time/right place-
if you had some sort of documentation- and it was in better shape it may be worth more- but with nothing other than...she thinks... it will probably not be worth as much as you would hope----unless of course a quilter who collects old quilt tops shows up at your sale & falls in love with it- but collectors generally want some sort of documentation.
you could see if you could locate a local quilt judge/appraiser & have it looked at.