It does not surprise me one bit that Antonio followed his father to find Lupito. He seems to have an inner side to him that makes him very curious and wants to know what is going on. Plus he is somewhat maturing and he prolly feels that he should be allowed to go with the men to find Lupito. I think his dream is just another way of telling him he will not follow his brothers, but will make his own way through life. I am not even sure that he will follow his mothers dreams. I think he will make his own path.
I was also worried that Antonio was going to be discovered and shot on accident while they were trying to ge to Lupito! He was very lucky!