Abnormal pap smears and cervical abnormalities are relatively normal. The good news is that for those women who get their pap smears every year - it is highly unlikely they would turn cancerous, because the doctors catch them soon enough during the yearly paps to remove them before they do so. However, when women have not had a pap smear in years, the likelyhood of those cell changes being cancerous when they do have their pap smear is greater. This is why yearly pap smears are so important.
The good news is that even if this is the case with your mom, all hope is not lost. The colposcopy and biopsy will tell your mom's doctor exactly where the abnormal cells are located on the cervix and how severe they are. Depending on those results, the doctor will most likely want to remove the bad cells. And as long as those cells are only located right in the cervix, no major surgury or treatment should be necessary. It's pretty easy to remove as long as it stays right in the cervix.
This is all pretty common and you guys will get through it. Hopefully, the cancer has not spread beyond the cervix and will be easily treated. Keep us updated.