If henbit is pulled out by the roots, that particular plant won't come back, but it sprouts readily from seeds that may lie dormant in the soil for many years. So new plants sprout in the area where the old ones were pulled out. If she is persistent and pulls out all of them for several years, the number of plants will start to decline. She could also apply a weed preventer to the area herself. The major flush of germination on henbit comes in early fall, so late summer is a good time to apply the weed preventer. However, henbit can germinate throughout the growing season, so a repeat application may be necessary.