This is exactly the issue. We already have family members making demands on our time that aren't even possible. My spouse is expected/asked to do work for other family members during the time that our young children are not in school (summer and breaks). Obviously my spouse (a teacher) is caring for them, but no one in the family ever recognizes this. It's so weird. Simultaneously we've been asked to contribute to other family members's financial needs. Even before we could actually afford to do so. Technically we still can't afford to do so because we are funding our retirement and childrens' college funds.
That is the very important reason why we don't tell people.