If an employee is covered under a spouse's health insurance plan, if he decides to come onto his group's plan during open enrollment, can the spouse cancel his coverage then or does the spouse have to wait until her open enrollment? Is this

If an employee is covered under a spouse's health insurance plan, if he decides to come onto his group's plan during open enrollment, can the spouse cancel his coverage then or does the spouse have to wait until her open enrollment? Is this a Qualifying Event?