Assuming the support test for FAFSA is identical to the support test for income tax purposes, how much someone earns is not relevant. How much they pay is the relevant question.
Only the amount the boyfriend pays towards health insurance premiums would count as support provided by him. If he has employer-paid health insurance, it’s my reading of the relevant IRS publication that those amounts are disregarded in determining support.
OP, here’s the Pub you can use to figure out what’s support and what’s not: https://www.irs.gov/publications/p501#en_US_2017_publink1000220972
And a more legible version of Worksheet 2: https://apps.irs.gov/app/vita/content/globalmedia/teacher/worksheet_for_determining_support_4012.pdf