Boyfriend's opened up... i need advice

My boyfriend told me the one thing he really struggled to say. He told me that he was raped repeatedly whilst in care by the foster parents son and his friend. My boyfriend broke down in tears, and has since gone into a shell. Im not sure what to do to help him. He told me its hard, and that since discussing it hes had flashbacks. I feel so helpless, he was strong and everything before he told me. Is it bad that i see hes weak right now and that i feel so helpless to give him the strength again. I need advice or suggestions on what to do