The Board of Trustees of the Alabama Institute for Deaf and Blind, upon the recommendation of the president, may select and adopt for use in the tax-supported public elementary and high school programs at the institute, textbooks and instructional materials, other than prescribed by the State Board of Education, which are suitable for the needs of deaf and blind students. Whenever textbooks and instructional materials are substituted for the state-approved or state-adopted books and materials, such books or materials shall be used by the teachers in the institute public school programs in teaching any course or courses for which a substitution has been made. Provided, however, such Board of Trustees of the Alabama Institute for Deaf and Blind shall provide free textbooks to all grades which would be provided under the terms of subsection (c) of Section 16-36-65.