The hand stitches are very small. It is surprisingly hard to remove those stitches!
If the fabric is sound - and the seams are pressed to one side - I think traditional hand quilting 1/4 inch away from the seams would hold things together nicely. The fabrics did not appear to be very prone to raveling.
If the fabric is weak - tears easily - I would not put any more effort into trying to make it into a usable quilt. If you want to frame it or do something to "just look at it" - that's another way to go.
In many garments, fabric is trimmed to 1/8 inch in grading - like in collars or facings - the seam is enclosed and usually survives nicely.