My son shouted who my daughter liked what should I do?

My son Matthew came over to my house to use my daughters computer. After he was done using it he looked at my daughters pictures on her computer. I don't know why he did that and there was a picture of Jake T Austin with a giant heart around it and it said I love Jake T Austin and it also said he was the hottest guy ever. And my son screamed Veronica loves Jake T Austin. She is very upset and embarred about this. She is crying right now. My daughter is 14 and my son is 20. I can't punish my son. What should I do. I told my son to leave. And me or my husband did not know she liked Jake T Austin. She is not the person who shares things with others.