I've seen it happen - I wouldn't call it a miracle, the relationship is still not comfortable or easy but the formerly-estranged parents really truly are making an ongoing effort to change and were even before they tried to reconnect, and the rebuilt relationship has been really valuable to my friend.

Also, I was one of the people the friend vented at during the estrangement (plus I was on their side! I wasn't going to like the person who hurt them that much!) and after they started on the new relationship, and I went along as backup a few times, it became clear that it wasn't quite as bad as I'd thought. (I mean, it was still bad, the estrangement was wholly justified, I still make sure I'm around and willing to believe the worst when needed! But I was only hearing the bad stuff cast in the worst possible light because that was what the friend needed me to hear and believe - I think even during the worst part of the estrangement, if you'd asked the friend they would have given you a better impression of the parent than I would have, because my job was to be the person who who hated them unconditionally for them.)

So if BF is starting to be willing to try again, LW may find they can follow BF's lead until it's not as unforgiveable or unfixable as they thought from secondhand.

Or they may find it's even worse than they thought. That is a lot more likely, I've been the friend from that side too! But unless there's actual fear of physical danger or serious financial hardship in going I think it's probably worth giving it one try to find out. Along with being there as support and backup and a getaway driver and an impartial witness.