Help identifying stitch

[Londa]

Can anyone help me identify the stitch used in this Afghan?  A friend of mine has asked me to see if I could fix it.  It was a gift grin her mother who has since passed away.

One area has come completely unraveled and the other just somewhat.  It may be hard to tell from the photos. 

I haven't crocheted in years, but I told her I would try.  I'm hoping I can, goodness I just don't know!

Any help would be greatly appreciated!  

 

[Granny Square]

I think the below is rightside up for the dark stitches that are unravelling.

If I were given this task, I'd find a sewing thread that matched and darn it, personally.  (1) this is going to be tougher to find matching yarn than thread (2) really, it's going to be nearly impossible to re-crochet this; it might be different if (example) it was a granny-square or other motif-style blanket, would be relatively easy to cut out a damaged square and make a new one with a little trial and error to get the gauge right, and sew it in.

To answer your question, it appears that the dark (black? blue?) area is a shell stitch (4 dc into 1 stitch, skip a stitch, sc in the next stitch, skip a stitch, repeat), and the rest looks like sc.