I can empathize with your dilemma. I once tried to duplicate a pattern for a crochet motif that my mom was making (for a tablecloth) before she passed away. I spent DAYS and DAYS on it, and finally got it. Of course I later found it in about six books!!!
Evidently it was hiding until I'd done all the work!
From what I can tell from the picture you posted, it looks very much like a Yarn Over Cable stitch. You can find it in several stitch dictionaries, but it just looks so similar. Hope this helps.
Multiple of 5 stitches + 2
Row 1 (Right side)
P2 *slip 1 as if to knit, K2, PSSO, P2 Repeat from * across
Row 2 - K2 * P1, YO, P1, K2 Repeat from * across
Row 3 - P2, (K3, P2) across
Row 4 - K2, (P3, K2) across
Repeat rows 1-4 for pattern
Let us know how it works out. The sweater you want to make for your mom sounds lovely! And regardless of her current condition, she'll know.
Best of luck,