Possible date rape and a BFP! Please help !

My sister was drugged at a local bar and isn't sure exactly wamart hapiened but she didn't go to hospital even though I begged her to. However she did just set up apt with her family doctor to test for STDS. She's been TTC for over 6mthz and is now scared her BFP could be a result of that. She just told her husband tonight and they are wondering what chances it could be. It happened 14days before she got a posotive OPK. They are going to keep baby no matter what. But since you actually don't ovulate until 24/48hrs after a posotive OPk chances aren't high. Anyways that's my opinion. Yes she should've mentioned it sooner but either way they are very catholic. They've only been with each other so it was very hard for her and she wouldn't have even taken a plan B pill. Anyways she isn't into technology so I said I would post this and see what others opinions are. Her and her husband also Bd everyday during fertile window so do any other women feel like it's a low chance(yes always a chance we know) it could be a result of the date rape? She isn't even sure something happened because she slept the next day away anyways! Please no hateful comments she will be reading and us very catholic do plan b and abortions aren't in option in this case even if it wasn't her husbands.