What is the federal law requiring employers to permit employees to continue their group health insurance coverage after termination?

The Consolidated Omnibus Budget Reconciliation Act or COBRA is what you are referencing. It allows you to keep your group coverage for a specific period of time provided you pay the premiums.

One very important point here that most people do not know. If you have a family that was covered on the group plan each is eligible independently, you do not have to enroll he whole group. Lilkewise you do not have o enroll the employee but can still enroll the dependents.

Say you have a dependent with ongoing medical needs but you are in good health and are willing to run the risk of going without coverage (NOT something I recommend). You can enroll that dependent only and drop coverage for yourself.

Also you have 60 days to enroll so take that time to look around for other options.