Sadly, there probably is not much you can do to stop him. You could attempt to talk to him and convince him not to interfere, but it is not likely he will listen to you.
Step uncle
u call your dads brother uncle in English
He had a half brother from his dads previous marrige.
niece/nephew
No, they are not brothers.
Brother-in-law
My father was my brother and my sister was my mother
Sister is 15, Brother is 17 not sure about his brothers on his dads side
John Terrys dads name is Ted. His dad and his mother (sue) split when John & Brother Paul were children.
yes he has a sister, well i think he does, he also has a young brother from his dads side
i call him uncle Micheal because he is my uncle and his name is Micheal
A Great half uncle.