Expanding Health Care Options for First Responders Act This bill establishes a Medicare buy-in option for certain qualifying first responders. Specifically, the bill allows first responders aged 50 to 64 to enroll in Medicare if they are retired or otherwise separated from service due to a disability. The Centers for Medicare & Medicaid Services (CMS) must determine enrollment periods and set premiums for the buy-in option established under the bill, in accordance with specified requirements. The CMS must also award grants to states and nonprofit organizations for outreach and enrollment activities relating to the buy-in option.