You want to protect your friend. I get it completely. Trying to figure out how to be there for your friend without overstepping your bounds, especially when you don't know where the boundaries are because you haven't seen them yet, is hard. You'll get there though. So long as you stay genuine with your friend the truth of your feelings will come across.

Although, you know you'll open a kettle of fish, don't you? If you've only seen the outside of what happened and you are reacting so strongly, you'll have to brace yourself, because when you make it plain that you want to listen and help, you might start hearing details that are even worse.