I love the colors in this quilt. And count your blessings your daughter found out about this guy before they tied the knot! It may be heartbreaking now but much less so than if the discovery of his past happened much later after they had children.
Gray can be iffy sometimes. I have found that I often need to audition gray by puddling a bunch of the thread on different areas of the quilt. Some grays are too brownish or tend to go to the warm color spectrum, others are the opposite and go to the cool and are too white or blue looking.
I have found that a soft gold seems to play nicely with everything, much like the shade of tan on your inner border. Another color that seems to go with everything is moss green or some people call it pea soup green.