The executive director shall provide detailed expenditure estimates of all anticipated hospital expenditures, all supplies, expenses, buildings, and improvements as required for the best interests of the hospital, and for the improvement of the hospital and of the grounds and buildings connected with the hospital. These estimates shall be submitted to the State Department of State Hospitals, which may revise them. The department shall certify that it has carefully examined the estimates, and that the supplies, expenses, buildings, and improvements contained in the estimates, as approved by it, are required for the best interests of the hospital. The department shall thereupon proceed to purchase the supplies, make the expenditures, or conduct the improvements or
buildings in accordance with law.