Tex. Estates Code § 257.054

An applicant for the probate of a will as a muniment of title must prove to the court's satisfaction that:

(1) the testator is dead;

(2) four years have not elapsed since the date of the testator's death and before the application;

(3) the court has jurisdiction and venue over the estate;

(4) citation has been served and returned in the manner and for the period required by this title;

(5) the testator's estate does not owe an unpaid debt, other than any debt secured by a lien on real estate, or that for another reason there is no necessity for administration of the estate;

(6) the testator did not revoke the will; and

(7) if the will is not self-proved in the manner provided by this title, the testator:

(A) executed the will with the formalities and solemnities and under the circumstances required by law to make the will valid; and

(B) at the time of executing the will was of sound mind and:

(i) was 18 years of age or older;

(ii) was or had been married; or

(iii) was a member of the armed forces of the United States, an auxiliary of the armed forces of the United States, or the United States Maritime Service.