Lack of interest in or concern about family members/matters.
Usually a temporary state of mind following prolonged or strained contact with them (e.g. Christmas, holidays).
Put simply, you can't be arsed to contact, visit or spend any time with them - they do your head in.
Bf: You gonna call your 'rents? You've not spoken to them in a while...
Me: Nah, since Xmas I'm suffering family apathy.