There are lots of exercises that she could do to help strengthen the ankle. I personally wear a brace on the ankle that I tend to twist a lot as it helps minimize the amount of injuries.
Physical therapy to strength her ankle, and possibly a visit to an orthopedist, to prevent further damage. If she keeps doing this, she may completely tear a ligament in her ankle. This happened to DD.
This is also my DD. We went to a place that did motion analysis on her whole body and her foot turn-out is the culprit for sprained ankles. Evidently, the fix was to work in PT on alignment and strengthening of her hips.