I would hang it outside for a day -- out of the sunlight -- and let it air out, and you might spray it lightly with Febreeze, as well and let it dry outside. Clean air may reduce the smell and some of the dirt may blow away, too.
That looks a little like handquilting. If so, you may want to keep as much of it as you can, since she did it. If not, then yes, I'd take it out and begin again.
Beautiful quilt! And I know you'll finish her work with love and compassion.