Familia mihi omnia means "family (with the restriction AS said... see
here for a complete definition of the word) is everything to me".
As other/more classical Latin translations I can propose
mei ante omnia = my family before everything;
meos ante omnia caros habeo = I hold my family dear before everything/dearer than everything.
Ante meos nihil = before my family (comes) nothing.
Or if you don't want "
my family" in particular but want the sentence to apply to everyone in general so just "family";
propinqui ante omnia/ante propinquos nihil, though it's perhaps less precise.