You could use bias tape to cover up the seams that have come open (or even straight grain strips).

I had a friend ask me to fix a quilt like that and I just used a thread that would blend and did a big zig zag over the seams.

Lots of folks use a fine tulle (netting) over areas of quilts they are trying to restore...it allows the original fabric to show, but protects it from rubbing wear and reinforces the area at the same time..it is tough! Might do some decorative stitching over it to further reinforce. I might even use invisible thread, or a variegated to blend in so it wouldn't be as noticeable as rick rack.

yep, ribbon or folded sashings you can stitch down over the seams. Good luck!!

I've had to do many repairs on a store bought quilt (before I learned to quilt). I just used a little glue to hold the seams together and used my Janome 6600 with the crisscross boxed stitch to go over the seams. Every time I wash it, I seem to have to do additional repairs though, but I still like the quilt, so I do it.

Years ago, I was watching one of the Alex Anderson shows and a suggestion was offered that you use a very light weight see-through veiling over the whole quilt to keep it intact. You would probably have to do something to cover up the batting that is showing through before you quilt on the see through veil material. This will only prolong the life of the quilt and may not be appropriate if the quilt is to be in use every day.