When filing a restraining order for rape, do you have to file a police report for rape?

You use the term "restraining order".  The term used in criminal law is "protective order."  Even though they sound very familiar, they are different in their proof requirement and duration.  If he was served with a "protective order," then his ex- had to have filed a complaint because the very first component of the Ohio protective order statute reads, "upon the filing of a complaint...." This statute allows the state to set protective conditions as part of someone's pre-trial release.  So, the ex-girlfriend cannot obtain a protective order without the complaint.  However, she could file a restraining order-- which tends to be more civil in nature, rather than criminal.  Just because she files for it, doesn't mean that she will get a final restraining order.  The fact that she's an adult and has waited several months to say anything is a factor that should way in your brother's favor.  The decision to grant or deny a protective order often comes down to "who does the judge believe."  Before a temporary or final hearing, you brother really should talk to an attorney who handles these types of orders and criminal law.  The first focus should be on gathering information to refut the need or allegation of rape.  Evidence would include her facebook page saying she was going to retaliate against him, or even the absence of records (like no phone calls or contact for the last five months.)  The second focus should be on making sure that your brother does not say something in these hearings that could subject him to criminal liability.  It he takes the stand unrepresented, he could say things, not realizing how they play into the other sides theory of how the "rape" occurred.  So, even though he hasn't been arrested at this point, the hearing could be a catalyst for charges if things don't go well.