Your greatgrandmother was quite careful to compose her blocks with stripes turned to please the eye...I can certainly forgive a tuck or two, can't you? Taking it apart is not going to strengthen it...I'm in agreement with you that it will not hold up for actual use, but it should be finished and occasionally displayed to be enjoyed and always cherished. Whatever you do to preserve it will be far better than leaving it in its present state. I'd consider using lightweight fusible stabilizer on the backside of the weak fabs... what is your plan for quilting? Consider the paint as beauty marks...that's a kind term for AGE SPOTS...the top has survived...scars, warts, neglect, and abuse...all of those are just as much a part of it now as the original work your ggm did...celebrate them and LOVE that top pretty...you can do it...you just have to want to! Thanks for sharing the photo and good luck!