14 year old cousin pregnant by 46 year old man, what should I do?

Hi, I have a 14 year old cousin who I am very close to, she is more like a sister. I am a 31 year old man. Last year she went out with a boy and the split up. She then became pregnant a few months later. Me and my brother and several other people are 99% sure that she became pregnant by her boyfriends father who was 46 and single and who we believe had an affair with her which continued for a few months after she split up with the boyfriend. I say 99% because he is denying it and she is keeping completely quiet about it saying it was a one night stand and she does not know who the father is although we have significant circumstantial evidence it was the 46 year old man but we do not have conclusive proof. I am extremely angry and feel like she is doing it to protect him as she must have had feelings, but what can I do? In my heart deep down, I know it was him but I cannot do anything? I was wondering if we could force the father to take a paternity test. I want to avenge him for ruining her life even though she is protecting him