DIFFERENCE BETWEEN A RELATIVE AND FAMILY....

Family denotes a group of people or animals (many species form the equivalent of a human family wherein the adults care for the young) affiliated by a consanguinity, affinity or co-residence. Although the concept of consanguinity originally referred to relations by "blood," anthropologists have argued that one must understand the idea of "blood" metaphorically, and that many societies understand 'family' through other concepts rather than through genetic distance.\

Note: Family does not have to be blood related, i.e. best friend, god brother or sister, play cousin.

Relative can refer to-

Kinship, the principle binding the most basic social units society. If two people are connected by circumstances of birth, they are said to be relatives

Kinship is a relationship between any entities that share a genealogical origin, through either biological, cultural, or historical descent. In anthropology the kinship system includes people related both by descent and marriage, while usage in biology includes descent and mating. Human kinship relations through marriage are commonly called "affinity" in contrast to "descent" (also called "consanguinity"), although the two may overlap in marriages among those of common descent. Family relations as sociocultural genealogy lead back to gods[1] (see mythology, religion), animals that were in the area or natural phenomena (as in origin stories).