You could also transfer the HSA balance to another provider, if you want, and have his business enroll you as a family in the plan. Additionally, you can choose to make a one-time (lifetime) transfer from your IRA to your HSA account, which sounds ideal in your situation. I am not sure what the limitations are for this transfer.
We were told by insurance that as the business owner he could not pay for health insurance pre-tax.
Sort of. If it's an S corp, your company _may_ pay for the plans and write it off as a business expense, but you still have to pay federal taxes (but not payroll taxes - see second link below) on it for shareholders/owners. If it's a sole proprietorship or LLC, or an S corp that paid regular wages, you can take the self employed health insurance deduction for it on your 1040. I use the second method.
https://www.irs.gov/publications/p535/ch06.htmlhttps://www.irs.gov/pub/irs-pdf/p15b.pdf"S corporation shareholders. Because you can't treat
a 2% shareholder of an S corporation as an employee for
this exclusion, you must include the value of accident or
health benefits you provide to the employee in the employee's
wages subject to federal income tax withholding.
However, you can exclude the value of these benefits
(other than payments for specific injuries or illnesses)
from the employee's wages subject to social security,
Medicare, and FUTA taxes."
Zane benefits offers some plans targeted to small businesses that help you navigate this.
https://www.zanebenefits.com/blog/are-health-insurance-costs-a-tax-write-off