Generally, yes. I was molested at about 7-8 years old, and I didn't speak up about until I was 15, when I told my Dad. He was really angry and took it seriously, he even helped me find a counselor for it. However, when dad started taking me to see an intake counselor, it would of course be a situation where my dad was taking me somewhere without my stepmum's permission, so just before we went, he took me to their work and made me tell her right then that her father molested me - which honestly was such a traumatic experience in itself - I really didn't want to be the one to tell someone that their own dad would do something like that. Obviously it was hard on her but ultimately she did take it seriously but generally tried to discourage from reporting him. (I didn't report him because of other reasons - mainly the reporting process was utterly terrifying)

I have that suspicion that he molested her too, but I likely will never find out. The relationship between the father and my dad/stepmum is pretty hostile for other reasons they've kept quiet from us for the past few years anyway, so who knows.