Family is who you make it out to be. Just because you may be related by blood, does not make them family. Anybody who has ever been kicked out of their homes for being different (I.E. coming out) can attest that they are no longer your family when their hate and ignorance overtakes any sense of love they have for an individual.
By ignoring COVID-19 and pretending it doesn't exist, they prove their ignorance flies in the face of not only reality, but any kind of love they had for that particular family member.
I do not consider my racist brother my family member, because what he has said, what he stands for, and who he follows like a fucking lapdog. He is a hateful, spiteful individual, and I consider my best friends more of my family than him, even if he's related to me by blood.
TL/DR: Family isn't tied by blood. It's tied by the bonds of friendship and love.