Facebook is usually more personal than Twitter, so a replacement for it often depends on getting others to move over also. Twitter is more dependent on who you follow there and if there are alternatives on the other platform.
I have tried Diaspora, Mastodon, Minds, Gab, Parler, Friendica, and some others. The issue was always lack of family/friends who would come over also or just the lack of what I use the original for anyway. The sites themselves usually worked perfectly fine and some better than Facebook/Twitter, but lack of interest from others made it hard to stay. For example, Parler and Gab both were fine but they lacked much in the way of sports reporting which is most of what my Twitter is used for (I follow 52 users there, probably 12 of them are Bama related, another 20 sports related, and the rest a mix of humor and a few local to me things). Nobody on my Facebook wants to move anywhere else, I only have 40 friends anyway, so I just stay there.
If your folks are leaving to go to the same places then try them out. Most are way better than Facebook or Twitter at forcing ads in your face for sure.