half blood brothers question

Doll • Premie baby born Feb 23. Due date April 15th. 🙏👶💙 Follow me on insta -ZULLYBRITO
Okay so this is not related to pregnancy but I'm curious.
So my dad is in jail for dui and he had 2 more kids with his ex gf and when my dad was out I would go sleep over visit them and stuff then hen he got in jail I stopped for 2 years in going , and I called my dad ex gf so I can see the kids She said her new husband won't let me cause the kids forgot about me and it would be something new so I can't see them anymore :( can I fight a case????