Is 1099-misc income from a former employer, Value of retiree health benefits, considered self income and needs to be reported on schedule C?

No.

If you receive a form 1099-MISC for health benefits, then you are not considered as self-employed and do not need to file a Schedule C.

In TurboTax, enter your form 1099-MISC and follow the interview until you arrive at the page titled Did this involve an intent to earn money?. Answer that this did not involve an intent to earn money. The amount will be reported as Miscellaneous income and will not be subject to Self-employment tax.

In TurboTax, there is a work-around. Although you may receive this income every year, say that you only receive the 1099-MISC only in 2021, not in previous years and not in 2022, you will then have the screen where you can say that it did not involve an intent to earn money.