I was asked to repair a very old quilt too; luckily the gentleman just wanted me to "sew patches over the bad areas". I could not do that. I picked out the bad places and got a jelly roll of 30's reproductions and stitched them in. Then hand quilted over the areas I had to tear out. He was thrilled with it. It did take time, yes, but I felt better doing it that way than patching it. I didn't rush to do it and he wasn't in a hurry. He loved the outcome. Good luck.