Questions: Family & Friends

So I’ve been dating my girlfriend for over a year now. She’s 20. In her house there’s her mom, stepdad, her full siblings ( 21 and 19) and half siblings (12 and 10) and her dad. Since I’ve been with her I’ve noticed she’s very close to her dad and when ever he texts she replies immediately. Her dad was 48 when he met her mom who was 23. Anyway, she was over at mine for 3 days and her dad texted her “I haven’t seen you for 3 days, I miss you” to which she replied (I miss you too, we”lol watch our show when I get back) it was weird for me since I thought it was awkward. Then realised every time she mentioned she was watching something with her dad, it was up in his room, on his bed with the doors closed. It made me really uncomfortable. I asked her and she got mad and asked me to tell him like she confronted. So I can’t even get through to her about this. She other 2 siblings are not that close. They are in their own world. She does his laundry, one day he came into the room with her underwear asking if it’s hers? Just using 2 fingers that was another incident. He always picks her up, drops her off, comes to see her everyday after he finish work, gives her sweets and gifts, and then I planned a surprise dinner one day. She had to be home for painting the house. She forgot, I was dressed, she went home her mom ( narcissist) wasn’t happy, her dad didn’t look at her and she stood there staring at him waiting for him to turn around to look, it was really weird. I feel like my girlfriend is being a wife emotionally for her dad. The other day she said “daddy got me this” and I asked what? And she said dad after. When we have intimate time she says dddy, so now it’s even more awkward. If her dad and she is home, they always do something together, go for drives or he tries to show off his skills. Awhile ago he asked her what cologne I use and he bought the same. I wait for her to finish to eat, he does the same. Please help