(1) In the event that a majority of the votes cast are in favor of the creation and establishment of said hospital district, the board of county commissioners shall, within 10 days after the election, certify such result by resolution and proceed with the organization of such district as specified in this part.
(2) After 20 days from the passage of such resolution, the validity of the creation of such hospital district and the regularity of all proceedings preliminary thereto shall not be questioned or asserted in any legal action.