I’m sorry this is late but if there’s a chance something can change I want to help. First since this post was made two days ago and this assault happened recently he needs to go to the hospital for testing for possible pregnancy and sexually transmitted diseases. Another thing is if he wants to get justice the police need evidence which can disappear after a couple days. You need to convince him that they need to tell his parents or authorities (anyone who can help). If it comes down to it if your guardian knows your friends parents I think you should tell them what’s going on so they can help. I don’t know his living situation but this is a big serious issue because if they don’t say anything the abuse may continue. After a big trauma like this they are still probably in shock and if they don’t get physical as well as mental help things will get worse.