Someones previous attempt at a repair with needle and thread. Do not repair this way it is more damage to the piece as it splits threads and you have to cut out more of the afghan to do a repair that doesn't do this type of damage or bulk.
Crocheting back in because this stain went all the way to the edge of the block no weave in required but lots of adding of thread. You add thread the way you would change a color in the last yarn over of the previous stitch. Also you do a slip stitch into the next stitch when finishing a thread off. You know basic crochet stuff there but just in case someone has that question.
The things one learns when working on repairs. I can tell someone tried to repair this before with a needle and thread and lots of knots not what I would recommend doing to an heirloom. Also this was a very used blanket. The person who had it first used it all the time and they got in and out of their bed on the right side of the afghan (when standing at the foot of the bed looking at it, left side if you are laying in bed looking at the ceiling) they sat on the blanket a lot, lots of wear on the middle and that one edge. They didn't fold it down at night to save it but pulled it up over them selves as all the damaged is at the head end of the afghan and the right side. Also the person who made it stopped for a long time and went back to working on it and forgot what size hook they had been using because there are two rows that have a bigger stitches and the roses are a different size than all the rest. Found out they ran out of green because there are two different greens in the afghan not nicely spaced all clumped together. Funny the things you learn when actually examining a piece of work this big. Also found out the original crochet was not found of finishing threads in a secure way as most have worked themselves out. I do not recommend just crocheting over thread ends weave some of them backwards it makes them stronger.
All done photos.
Tutorials on this repairIntro
Part 4 this post