Texas Insurance Code - INS § 1271.006. Benefits to Dependent Child and Grandchild

(a) If children are eligible for coverage under the terms of an evidence of coverage, any limiting age applicable to an unmarried child of an enrollee, including an unmarried grandchild of an enrollee, is 25 years of age.  The limiting age applicable to a child must be stated in the evidence of coverage.

(b) A health maintenance organization may provide benefits under a health care plan to an enrollee's dependent grandchild who is living with and in the household of the enrollee.