Remember Joseph brothers and his father was still in the land of Canaan. A famine touched their land and they were in need of food. Joseph being overseer of Egypt had stored up food because he knew the famine was coming. His brothers in search of food went to Egypt because of their surplus.
They didn’t know Joseph, for it was roughly forty years later, and he looked like an Egyptian. All but one of his brothers came to Egypt; only Benjamin stayed in Canaan with Jacob. Joseph remembered the dream that they would all bow down to him; so he told one of his brothers to go back and get Benjamin also. When they were all there, he confessed to them who he was and asked how his father was doing? Out of fear his brothers didn’t reply; they thought he was dead.
“And Joseph said unto his brethren, I am Joseph: doth my father yet live? And Joseph said unto his brethren, Come near to me, I pray you. And they came near, And he said, I am Joseph your brother, whom ye sold into Egypt. Now therefore be not grieved, nor angry with yourselves, that ye sold me hither: for God did send me before you to preserve life.” (Genesis 45:3-5)