Under current rules family members of positive Omicron cases don’t need to isolate if under 18 or jabbed.
Seeing as Omicron is evading vaccinated and boosters, if you had a positive result for it would you
YABU - attend a family dinner/ socialise even if a member of your household has the omicron variant
YANBU - Self-isolate too and not put others at risk of an awful Xmas/NYE (even if you don’t have to)
I’m of the opinion that you should SI to safeguard others as the likelihood you’ll catch from family member/child is likely with this variant, but curious to see others opinions.