He probably gets his health care coverage from his wife's plan. The federal coverage uses a menu of private plans that you can change on a annual basis. The USG pays about 70% of the costs. It is quite conceivable that Brown has access to a better plan at less cost.
The fact that Brown uses this as some sort of altruistic act raises red flags to me. I would like to see what health care plan he has and what he pays for it.