가족상황 is family relation. If you were to directly translate each word, it would be 가족(family)+상황(situation). However, it basically refers to the family relation. To add more, family is 가족 and relation is 관계.
we do not quite use the word 가족상황 in our daily life, but I would assume that the textbook was referring to the family relations instead.
For example, there's 가족 관계 증명서 which is an official document that the government issue to prove your family registry.
가족 관계 증명서 is officially translated as Family Relations Certificate in English. This document contains information about your direct families such as Father, Mother, Spouse, and Child. So, 가족 관계 refers to your relation to the direct families.
혼인 관계 is marital status. Again, there's 혼인 관계 증명서 which is an official document that the government issue to prove your marital status. 혼인 관계 증명서 is officially translated as Marriage Relation Certificate. This document contains information about yourself and your spouses only. Your kids or any other family members would not be addressed here. So 혼인 관계 refers to your marriage relation.