mini I agree we don't know.
I am quite happy to agree that if the father just lives round the corner and this is just selfishness, then it would be better for the child to sleep,overnight with her mother. Even then, I would say he deserves a decent slug of access during the day.
W speculated above that it might be about there being a big commute for the father, such that overnight stays are the only way forward. Either the mother or the father may have moved away. If that were true, I'd be more worried about the long weekly commute for a child at this age.
But the thread does seem to be assuming the opposite- that there is no barrier to the fathers access if BF continues. I think that is a big assumption, and not justified by what we know.
Of course, it would be ideal if daddy lived nearby, access could be amicable and BF could continue. But I don't think that is where these parents are. So yes, I think it is highly likely that it is a choice between a relationship with her dad and BF. in which case, I would say that the relationship with the dad has to come first.