What should I do in this situation?

No matter what happened between your real father and your mother it doesn't concern you, you have the right to know who your real father is? This German man can not be your father why did she lied to you that your father is dead? As you are almost 30 or even had it been that you were younger you deserve to know the truth. I feel there is something she is hiding. dint you have any relation you can inquire?