Yes... as japdip says, it all depends on how your mom feels about the 6 follow-up month wait-and-see approach. If she's finds that 6 months is too long of a time to wait for the follow-up, then a biopsy can be performed in order to find out sooner rather than later what the nature of the calcifications are. Just so you know, microcalcifications are rarely found to be cancerous... however, when they appear... especially, in clusters... it does give cause for concern because it suggests that an abnormality within the surrounding breast tissue is triggering their growth. Therefore, they're an abnormality that should, at the very least, be monitored. And, in many cases, biopsied. My best wishes to your mom.
If your Mom is comfortable with the recommendation of her Dr. about the finding then I see no reason not to wait the 6 months. This is often advised to ck. for any change in the area in question. If she is worried too then she could ask to be checked in 3 months OR even see a Breast Specialist for a second opinion. Regards .....