(a) Except as provided by Subsection (b), a parent who is the guardian of the person of a ward who is 17 years of age or younger may not use the income or the corpus from the ward's estate for the ward's support, education, or maintenance.
(b) A court with proper jurisdiction may authorize the guardian of the person to spend the income or the corpus from the ward's estate to support, educate, or maintain the ward if the guardian presents to the court clear and convincing evidence that the ward's parents are unable without unreasonable hardship to pay for all of the expenses related to the ward's support.