How is this complicated? It’s very specifically defined. Is there any way to misinterpret it?
(2) Any individual who holds an individual license may allow his or her immediate family members to operate his or her GMRS station or stations. Immediate family members are the licensee's spouse, children, grandchildren, stepchildren, parents, grandparents, stepparents, brothers, sisters, aunts, uncles, nieces, nephews, and in-laws.
I thought the cousin-wife thing was funny.