1 Answer. 0. A. If an incapacitated unmarried child who is covered under the policy reaches age 21 or 23, his/her coverage will not terminate due to age if he/she continues TRICARE eligibility due to the incapacity.. A. If an incapacitated unmarried child who is covered under the policy reaches age 21 or 23, his/her coverage will not terminate due to age if he/she continues TRICARE eligibility due to the incapacity.