My mother has two uterine fibroids. she is taking the treatment for 2.5 years. is it dangerous if not operated?

Generally not: Fibroids are benign growth from the muscle layers of the uterus. They are not cancerous but do cause other problems such as heavy painful periods, anemia, lower abdominal pain/discomfort (depending on the size), pregnancy and fertility problems amongst other things. There are multiple treatment options (non surgical and surgical). Your mother should discuss this with her OB/GYN.