There are other online brokerages, both large and small, that can help you sort out the individual market health insurance options available in your area. Most of them can show you plans that are available in the exchange as well as options that are only available outside the exchange (no subsidies are available outside the exchange, but as noted above, you're probably not eligible for subsidies anyway, if you have access to an employer-sponsored plan).
But it's also worth noting that if they keep the employer-sponsored plan for the whole family, the premiums will almost certainly be payroll deducted on the pre-tax basis. On the other hand, if they opt to buy an individual market plan, the premiums would only be tax deductible to the extent that they (along with other medical expenses) exceed 10 percent of the family's household income, and assuming that the family opts to itemize their tax deductions (increasingly rare now that the Tax Cuts and Jobs Act has greatly increased the standard deduction).
Individual and family health insurance plans can help cover expenses in the case of serious medical emergencies, and help you and your family stay on top of preventative health-care services. Having health insurance coverage can save you money on doctor's visits, prescriptions drugs, preventative care and other health-care services. Typical health insurance plans for individuals include costs such as a monthly premium, annual deductible, copayments, and coinsurance.