If you were the beneficiary of the HSA, code 4 is incorrect. Code 4 is only to be used for a distribution paid to the estate of the decedent. An HSA distribution was truly made to your wife's estate, the distribution was not eligible for rollover you your own HSA (at least not without an expensive Private Letter Ruling, but likely only if you were executor and sole beneficiary of your wife's estate).
If you were the beneficiary, the HSA should have been moved to your HSA by nonreportable trustee-to-trustee transfer, in which can no Form 1099-SA should have been generated. By operation of law, if a spouse is the designated (or default) beneficiary, the HSA automatically becomes an HSA of surviving spouse. The HSA can subsequently be moved by distribution and rollover, reported with code 1 on the Form 1099-SA, but it is better to move an HSA by nonreportable trustee-to-trustee transfer.
If the HSA custodian issued the Form 1099-SA inappropriately or incorrectly, contact the HSA custodian to obtain a corrected form. However, apparently so many HSA custodians mistakenly use code 4 inappropriately that TurboTax allows a code-4 distribution to be indicated as rolled over even though a true code-4 distribution is not eligible for rollover.
