Indiana Code Title 36. Local Government § 36-10-4-31

Sec. 31. (a) If a person having an interest in land affected by the proceedings is mentally incompetent or under eighteen (18) years of age, the board shall certify this fact to its attorney.  The attorney shall then apply to the court and secure the appointment of a guardian for the person.  The board shall give notice to the guardian, who shall appear and protect the interest of the protected person.  However, if the protected person already has a guardian, the notice may be served upon that guardian.  The requisites of notice to the guardian are the same as for other notices.

(b) If there are defects or irregularities of any kind in the proceedings with respect to one (1) or more interested persons, they do not affect the proceedings as to any other person.  In case of a defect, supplementary proceedings of the same general character as those already prescribed may be had in order to cure it.