Probably. Most people are eligible to buy a plan on the health insurance marketplace. However, depending on your household income and his access to other coverage options, he may not be eligible for premium tax credits to lower the cost of a marketplace plan. For example, if he is eligible for Medicare, he would not be eligible for premium tax credits. However, if he’s not eligible for Medicare and doesn’t enroll in your retiree health plan, he could be eligible for premium tax credits, assuming your household income is between 100 to 400 percent of the federal poverty level. (26 C.F.R. § 1-36B-2).