How can i find my long lost half sister and brother ?

[AC Question]

I have a long lost half sister and brother and all i know is that they are older than me and that we share the same dad. My parents don't want to tell me about them. Is there any way i can find them?

 

[the tall guy]

re:

Probably won't find them on an Android forum if I'm being honest, but you never know - register an account just encase

Have you tried things like Facebook??