Just be careful not to push things so hard you alienate people!

I find its most productive to share my joy or passion for things (like the Fediverse), and look for ways to relate those things to their interests and values, and if they get interested that's awesome!

Don't treat it as a failure if they don't they don't immediately switch. Don't pressure them. Don't try to make them switch while pretending you're just excited about it (people can tell when the subtext is that you want them to do something)

Share your joy, and if it seems like they have any interest or can connect with the appeal of it, ask them if you can set up an account with/for them! Not to try and make them drop Facebook, but to share why you care about this thing and participate in it together :)

That being said, it will of course depend a lot on the nature of your relationship with people. Your relationship with your mom might be such that she'd happily switch if she mostly just uses facebook to keep up with you and would be receptive to doing that a different way. And it's not necessarily bad to talk about why meta/facebook sucks, just be mindful of conveying preachyness, or making people feel overly presured to do what you'd like