Personally I think it’s a good thing to post some Catholic things from time to time on facebook, not with the hopes of doing much evangelization or debating. But I’m pretty sure at least 95% of the people of my facebook friends list have no regular exposure to anything Catholic, so just some quotes here and there from Scripture and the Saints, could have a big effect for such a small thing, just so it’s on peoples’ minds and maybe plant some seeds. If you take care, you can have a big effect with relatively few actions. Them reading a little bit of Catholic wisdom here and there is a whole lot better than nothing at all. I make a post about every couple days, whenever I happen to come across something good in my personal reading; that way it doesn’t become a big distraction from what’s most important, although I admit I might spend too much time sometimes overthinking my posts.
As for their attacks, perhaps it’s an opportunity to show a good example. If you’re able to clearly and respectfully defend the Church’s position, it could quite a bit of good. If they’re really overwhelming you and ganging up on you, then maybe wait til after they throw all their objections at you, then read through them, and instead of responding to everyone individually, respond to them as a whole with a summary clarification of the Church’s teaching, so you don’t get caught in a big web of debates.
Hope something here helps.
Sounds rough! I’ll pray for you and your family.
God bless!