A number of years ago I repaired a quilt that belonged to a couple who were friends of mine. To them it was a special quilt as it had been given to them from a church group when they left the church. It was not nearly as bad as the one you showed but I did take out the "bad" pieces and matched fabric as best I could. Found a yellow that was almost an exact match. Then I removed the torn fabrics and quilted stitches that were on that fabric and hand sewed the new pieces in the empty spots. Then I quilted the new pieces just as the old ones had been. Surprisingly it turned out quite well and the couple were very pleased. I did tell them not to actually use it as it would not be strong enough to withstand use or washing. It all depends on how much time and effort you want to put into it and whether you could actually find similar fabrics for replacement. Good luck no matter what you decide.