When I write, "my father-in-law, Nat Brandt." Do I capitalize father-in-law?
Students: Are you brave enough to let our tutors analyse your pronunciation?
No. Emotion: smile You were correct with capitalizing "Nat Brandt"

When I write " reside with maternal grandmother Terry Deer. do I capitalize maternal grandmother?

No, you don't.

Students: We have free audio pronunciation exercises.