Retirement tax questions

There is no place to enter a Box 7 amount on a 1099-Misc entry in TurboTax.  Your employer should use Box 3 to report this payment to you. 

You could report this income under 'Miscellaneous Income' on the Wages & Income topics page (at the bottom of the list).  Choose Edit/Add. 

Scroll all the way down to 'Other Reportable Income' and enter a description of Retiree Reimbursed Health Insurance and the amount.

At least this way you are reporting the income (since you no longer receive a W-2) and have the 1099-Misc for documentation if needed.