My father is allegedly accused of rape, what are the step we could do?

My 16 years old cousin was caught with her 28 years old boyfriend, my family plans to consult DSWD with what happened. Then few days after the incident my cousin then claimed that my father rape her multiple times.We all now that there is no such rape happened because the only incident she described was the day we all went on a family gathering- so here is what happened during the day of family gathering, it was my lola's birthday (the mother of my father) my father was already drunk but not that drunk to not remember what really happened that day, my cousin was lying on the floor and my father was looking for a "tawas", my father asked my cousin to moved so that the door will open but then my cousin won't moved around so then my father pulled my cousin but then accidentally he pulled my cousin's shorts and that was what my other cousing saw already. So now, they accused my father of raping her. We already talked to the family, my cousin will be having a medical exam but the alleged rape happened last May 2024, what will we do now?