Use a Health Savings Account to Pay Medicare Premiums Tax-Free
Answer: After your wife turns 65, you can use money from her HSA to pay Medicare premiums for both of you. And even though your premiums are deducted from your Social Security benefits, you can withdraw money from the HSA tax-free to reimburse yourselves for the Part B premiums. You can also use the HSA money to pay Part D premiums for both of you, as well as premiums for Medicare Advantage plans (but not medigap).
Keep in mind that your wife will no longer be able to make new contributions to her HSA after she signs up for Medicare.