The bylaws of an association may prescribe other qualifications for directors, but no person is eligible for election as a director unless he is the owner in good faith and in his own right on the books of the association, either in the form of a savings account or permanent capital stock, or a combination of both, having a value on the books of at least one thousand dollars ($1,000) which shall not be reduced by withdrawal or pledge for a loan by the association so long as the person remains a director. Any director who, after his election as such, ceases to be the owner in his own right of the necessary qualifying interest, shall cease to be a director, but no action of the board of directors shall be invalidated through the participation of such director in the action. If a director becomes ineligible under the terms of this section by reason of the exercise by the association of the right of redemption of savings accounts, he shall remain validly in office until the expiration of his term or until he otherwise becomes ineligible, whichever occurs first. Any vacancy among directors may be filled by a majority vote of the remaining directors, though less than a quorum, by electing a director to serve until the next annual meeting of members. In the event of a vacancy on the board of directors from any cause, the remaining directors have full power to continue direction of the association until the vacancy is filled.