Prob. Code, § 2552

(a) The guardian or conservator may give a security interest or other lien upon the personal property of the estate or any part thereof or a mortgage or deed of trust upon the real property of the estate or any part thereof, after authorization by order of the court as provided in Section 2551, for any of the following purposes:

(1) To pay, reduce, extend, or renew a security interest, lien, mortgage, or deed of trust already existing on property of the estate.

(2) To improve, use, operate, or preserve the property proposed to be mortgaged or subjected to a deed of trust, or some part thereof.

(b) If property of the estate consists of an undivided interest in real or personal property, or any other interest therein less than the entire ownership, upon a showing that it would be to the advantage of the estate to borrow money to improve, use, operate, or preserve the property jointly with the owners of the other interests therein, or to pay, reduce, extend, or renew a security interest, lien, mortgage, or deed of trust already existing on all of the property, the guardian or conservator, after authorization by order of the court as provided in Section 2551, may join with the owners of the other interests in the borrowing of money and the execution of a joint and several note and such security interest, lien, mortgage, or deed of trust as may be required to secure the payment of the note. The note may be for such sum as is required for the purpose.

(c) No omission, error, or irregularity in the proceedings under this section shall impair or invalidate the proceedings or the note, security interest, lien, mortgage, or deed of trust given pursuant to an order made under this section.