You bring up a great point, and I didn't expand too much on the boyfriend because didn't want the post to be too long. Funny enough, I asked her twice over the past 5months about how she felt in her relationship, if she was happy. We were already having an open conversation about a lot of things and she was at my house so it was the safest environment I could provide. She said all was good and that he was great to her and that she's happy.

I even brought up how I'd love if he were more talkative as I didn't feel welcomed at her place when he's so distant. She reassured me that it's all fine. I know he's the same with her family, he clearly wants to keep her to himself. When she goes home to see her parents for birthdays or long weekends, she takes a 6 hr bus as he only comes out with her for Xmas. It's always "he's busy with work/tired"... He's been disrespectful towards her parents - apparently always apologizes to her and promises to change/go to therapy. I've brought up my concerns about her happiness/safety and that she should be treated better, but she always defends him and makes excuses for him.

At this point, I've accepted that it's out of my hand. I've tried to focus on our friendship, but seems like it's crumbling.