The Holy Spirit has shined apon us the truth about these things. And really it is only the Holy Spirit that can open us up to believe something as insane as this and that it is actually the truth.
I had a set of rosary beads that I carried home from Medjugorje. The links of these beads turned gold as I was watching. I saw them change colour with my own eyes. I showed them to my brother who has always been there for me and supported me. He took one look at the beads and said "bullshit"
I honestly don't care if the beads changing colour are a conspiracy by rosary bead manufacturers ( which it isn't because I also saw a hand made set change colour) because at that very moment I needed the beads to change in order to give me a boost to maintain the faith. It was the Holy Spirit giving me what I needed to get me over the line.
I think the Holy Spirit talks to each of us in a way we can understand. Some people get the spinning sun or golden rosaries of scents of roses. There's as many ways as there are people that He can whisper to your heart. So in conclusion if your brother tells you its bullshit when your heart tells you it's truth then agree to disagree with your brother. That's what Medjugorje seems to be about believing the unbelievable and putting our trust in God.