5 CFR §890.1417

1. (a)An FEHB enrollment cannot be continued into retirement from employment with a tribal employer.
2. (b)A Federal annuitant may continue FEHB enrollment into retirement from Federal service if the requirements of 5 U.S.C. 8905(b) for carrying FEHB coverage into retirement are satisfied through enrollment, or coverage as a family member, either through a Federal employing office or a tribal employer, or any combination thereof.
3. (c)A Federal annuitant who is employed after retirement by a tribal employer in an FEHB eligible position may participate in FEHB through the tribal employer. In such a case, the Federal annuitant's retirement system will transfer the FEHB enrollment to the tribal employer, in a similar manner as for a Federal annuitant who is employed by a Federal agency after retirement.
4. (d)A tribal employee who becomes a survivor annuitant as described in § 890.303(d)(2) is entitled to reinstatement of health benefits coverage as a Federal employee would under the same circumstances.