Very similar situation here too.
Dp has two dds. I have two dds as well. Mine live with us. His oldest is an adult (was 16 when we got together) and is fine, is in regular contact, great relationship with us all and she is happy living her life with her boyfriend.
His youngest is a whole different kettle of fish. She's 13, was 8 when we got together. Her parents had split when she was 5 (mums decision) and I honestly don't think she's ever accepted that her dad has someone new. Her mum had moved on before him, I'm not sure how well she gets on with her stepdad but from snippets I've heard from the oldest, she's pretty disrespectful to him at times. She hasn't stayed with us now since December. She came here for four days after Christmas and kicked off massively because dp wouldn't let her spend two of those days at a friends house, sleeping over. He had no problem with her going out with friends during the day but wanted to actually spend time with her while she was here as well. Before that it was September last year, she was here for a week and that ended badly with her accusing me of stealing loads of her stuff (iphone charger - I don't have an iphone, it would be no use to me, socks - 14 pairs!, keys for her house - again, no use to me and her jacket - which wouldn't fit me anyway). Her dad actually backed me up for once and I think that was the point that she started pulling away.
Dp has been the ultimate bloody Disney dad and I've told him til I'm blue in the face that it wouldn't end well. If he'd put his foot down from the start then it would more than likely be better now but he never said no. He never backed me up. And now he's done both and she's 13. She won't even talk to him on the phone.
He sees her sometimes at a club my dds are at but she won't initiate conversation. He's asked her why she won't come here anymore. She says it's because it's too stressful. DD2 has autism and can be hard work but I deal with her and the last visit in September I actually made sure DD2 was out a lot of the time, took her out with me for the day, teen was working and dp was left home with his dd and they had the option of going out if they wanted. He sat downstairs. She sat on her laptop upstairs on skype the entire bloody week.
I've reached the point where I know the only communication we will get is what she wants for Christmas and her birthday. She doesn't bother with fathers day or her dads birthday. Nothing. It hurts dp a lot. She blames me and my dc for her not coming here but it doesn't explain the bloody awful behaviour she's displayed in the last year towards her own dad.
At least your dp sees his child. Mine doesn't.