The big diff is that by keeping an employer plan, he may be keeping "other" ancillary benefits, for example, a dental and vision plan. Plus, able to keep spouse and kids/dependents maintained on policy. It is far less expensive than even a "free"
MA plan plus individual insurance for family. Although
MA requires no qual, a med supp will. All employer group plans will shift to Medicare pay first upon client attainment of qual. Some will also pay for the Part B charge. Nutshell, don't have client cancel/switch out of retiree group/employer coverage before understanding full implications. Many employer plans will NOT allow retirees to switch back.