I became a "Chozer Be’Tshuva" three years ago and went to study Torah in israel. When I came back from israel I was already religious. Here in the Galut I am helping my father’s family business. The business requires working on Shabbat.I am trying to explain to my father that i can not work or employ other people on Shabbat. My father needs my help but I Can’t decide what to do. What can i do, I can’t just tell my father that I cant help him?

I fully appreciate your intricate situation and understand its complexity. Unfortunately, with all the difficulty of the family relations, there is no way you can work on, or break Shabbat. You will have to explain to your dad how much you love him and try to help him in any other way but ask him do understand where you are standing and to respect your beliefs and values. There might be a possible solution if your father will sell his Shabbat share of the business to a Non-Jew. These are complex Halachot and require a competent rabbi how knows the situation and the business' nature to assist you with that.