My sister in law has thyroid cancer which has spread to her bones and spine also she has cervical cancer and uterine cancer we want to know the rough time scale we have left for her?

No way to tell. If she's relatively young, the possibility of li-fraumeni affecting the family is a concern. But there is no way, even if i had much more information, that i could tell you how much longer your loved one has with you -- even chief justice rehnquist survived a few years longer than he was supposed to. Cherish every day you have with her.
Needs more info. metastatic thyroid cancer, can have variable prognosis and dependence upon the type of thyroid cancer.
We will need specific information to onset this question appropriately, will need to discuss with her endocrinologist and oncologist.