Ask what help they would like. Do not distract yourself with heroic fantasies to beat up the perpetrator. Offer to make an appointment with them to see a counselor, clergy, police, etc. You don't, even if you're a survivor yourself. Suggest counseling in addition to talking to you.
Professional counselors are very useful.
There is no limit to how long the healing process takes. Don't assume for them what they need. Give them time and space. If you're talking more than they are, you're probably not helping. Do not give advice, even if asked for it.