Yes they can. People who are eligible for employer-sponsored coverage can still qualify for Marketplace premium tax credits if the employer-sponsored coverage is considered unaffordable.
The affordability test will look at the cost of self-only coverage for you, and at the cost of family coverage for your spouse and kids. Because your employer pays 100% of the premium to cover you only, you will not be eligible for premium tax credits. However, if the premium contribution you would have to pay to cover your spouse and kids under your employer plan is more than 9.12% of your household income in 2023, their coverage would be considered unaffordable and they could qualify for premium tax credits through the Marketplace.
Browse more questions in the Employer-Sponsored Health Coverage section.