No, it is not if the s corp shareholder is eligible to be covered for a health plan with the spouse's employer.
"But if you were also eligible to participate in any subsidized health plan maintained by your or your spouse's employer for any month or part of a month in 2020, amounts paid for health insurance coverage for that month can't be used to figure the deduction. Also, if you were eligible for any month or part of a month to participate in any subsidized health plan maintained by the employer of either your dependent or your child who was under age 27 at the end of the year, don’t use amounts paid for coverage for that month to figure the deduction."
For additional information refer to the following link for the tax year 2020 General Instructions for Form 1040:
IRS General Instructions for Form 1040 pg 88
