Tex. Insurance Code § 1252.102

(a) A health benefit plan must contain, subject to this section and Section 1252.103, a reasonable provision providing for an extension of benefits for a total disability that exists on the date of the plan's discontinuation.

(b) A health benefit plan must contain a reasonable extension of benefits provision for coverage for hospital or medical expenses other than dental expenses. A provision is considered reasonable if it provides to an individual who is covered under the plan and who is totally disabled on the date of the plan's discontinuation an extension of benefits for expenses incurred in treating the condition causing the total disability and the extension is provided for at least the lesser of:

(1) 90 days; or

(2) the duration of the total disability.

(c) An extension of benefits provision required under this section may provide for an exclusion from coverage for an individual whose coverage is being discontinued and replaced with coverage that:

(1) is provided by a succeeding carrier; and

(2) provides a level of benefits that is at least substantially equal to the level of benefits provided under the replaced health benefit plan.

(d) An applicable extension of benefits provision must be described in the policy or contract and the group insurance certificate.

(e) Benefits payable during an extension period may be subject to the regular benefit limits of the health benefit plan.

(f) This section does not apply to a health benefit plan that was delivered or issued for delivery in this state before January 1, 1982, and whose level of benefits has not been modified after December 31, 1981.