Just be aware that your father with very probably chose this woman over you. My father did this after my mother passed away. Within a few days of her death a woman was sat on my mums chair in his house - she was a 'family friend' who had come to pay her respects (fine), within a few weeks my father was dating her. My brother and I kept quiet and didn't make too much of a fuss as my dad had been unhappy in his marriage with my (alcoholic) mother - we knew that.
I accepted her but she was icily polite towards me and her body language and the way she spoke to me was clear that she tolerated the closeness my dad and I had but didn't like it at all.
A few months later he asked me to come and clear my mothers things out. I had a quiet and private word with him about being very careful about moving this woman in.
Everything I said to my father he went and repeated to his GF and she went ballistic. I told my father that I wanted nothing to do with her as she is nothing but a troublemaker (she couldn't wait to find something that she could start against me, I could tell that)
Effectively she has managed to completely turn my father against me, and because he only thinks with his dick he listens to everything she says.
He hasn't spoken to me or seen his only GC's for nearly a year now and she is like the cat that's got the cream by all accounts.
Shes moved into his home, erased every trace of my mother and spent a huge chunk of my fathers money that he got from an endowment after my mother died on home improvements. She will not be happy until shes completely taken my fathers house over. He's a goof 10 years older than her so I think it was the plan all along. Its not the money at all that is the issue with me - its the way that my father was so happy to let his relationship with me, my DH and children get cut just to keep her happy and in his bed.
I just hope karma really does work.