Provided , That the cancellation or qualification cannot be set up against a third person acting in good faith. A feeble minded person or a spendthrift who may bring proverty to himself or his family, shall be adjudged a quasi-incompetent by a court on the application of the person himself, his spouse, any relative within the fourth degree of relationship, guardian or a public prosecutor. The provisions of Articles 5 through 8 above shall apply mutatis mutandis to the quasi-incompetent persons. When the cause for quasi-incompetency has ceased to exist, a court shall rescind the adjudication ao the application of any of the persons mentioned in Article 9. A person in a habitual condition of mental unsoundness may be adjudged incompetent by a court on the application of any of the persons mentioned in Article 9.
Juristic acts done by incompetents are voidable.
The provision of Article 11 shall apply mutatis mutandis to incompetents. The other party to an act performed by a person under disability may, after the latter has become a person of full capacity, give a peremptory notice to the latter requesting a definite answer within a period, which shall not be less than one month, as to whether the latter ratifies the voidable act or not. If the person who was under disability, fails to dispatch a definite answer within such period, the act is deemed to have been ratified. Before the person under disability has become a person of full capacity, the notice under the preceding paragraph may be given to his legal representative, and when his agent by law fails to dispatch a definite answer within such period, the act is deemed to have been ratified. Any act for which special formalities are required shall be deemed to have been avoided if a definite answer in compliance with such formalities is not dispatched within the aforesaid period.