Have you tried sitting down and crocheting with her? Or in front of her (if she won't do it) just so she can watch you and maybe get the urge to crochet again? Have her take a look at your yarn stash. Maybe she just needs to get the materials in her hands to feel inspired.
Or maybe she has bad associations with crocheting that you never realized. Maybe she felt it was chore. Does she have any friends who you could invite over to crochet with her, or you? That might help.
Keep trying. Maybe she'll warm up to it. It's sweet of you to want to help her.
That's a really beautiful scarf! This is your first scarf? Have you done other crochet projects before doing this or is this your first attempt? If it is, that's quite the stitch to try for your first one. My first scarf was a combination of single and double crochet stitches and was no where as nice as yours. Great work!