A probate guardianship is a formal court process in which the probate court appoints a guardian to have custody of a minor and or their property (California Probate Code §1510). A court's appointment of a guardian of the person or estate, or both, lasts until the minor's 18th birthday. (California Probate Code §1600). Any relative or "other person on behalf of the minor" may file the petition (California Probate Code §1510(a). One petition may be used to request the appointment of a guardian for more than one minor, if the minors are siblings. (California Probate Code §2106). The probate court has the discretion to appoint two or more joint guardians for the person and or the estate of a minor. (California Probate Code §2105). Each of the proposed joint guardians must qualify just as would a sole guardian.
In deciding whether a guardian of the estate should be appointed the "court is to be guided by what appears to be in the best interest of the proposed ward, taking into account the proposed guardian's ability to manage and to preserve the estate as well as the proposed guardian's concern for and interest in the welfare of the proposed ward." (California Probate Code §1514(e)(1))