Here is a link to the TCA web site. Someone there should be able to help you.
Last I knew, a member could register their spouse and children (under a certain age) as family members. I took a look at the online membership application and did not see any mention.
I never signed up my wife or kids as family members, I didn't think there was any benefit to doing so.
My kids were members of the TCA Kids club until they aged out.