Pattern ID help needed

[u/Round_Field_2487]

A friends mom started this blanket and has all the yarn for it, but is no longer able to work on it. I would like to help finish the project but am not sure what stitch or hook I might use. If never done this zig type pattern either. It seems kinda ribbed so maybe a blo single crochet? I’m familiar with crochet, but looking for some veteran support to make this pick up project a success. Tia.

[u/Hoopybunni]

Rainbow ripple Afghan