Far more detail is needed here.
What are the exact cirucumstances of your friend's dd coming into your care? You say you've known for weeks it could happen, that's not that long for a situation so life-changing. Has a tragedy or illness precipitated this happening (my truly deepest sympathies if so)? If yes, was there a prior agreement in place that you and the dp would take the child in in the event of something like this occurring? Or has he been asked to take in the child of your friend as a result of a sudden, unexpected occurence, and perhaps pressured by a tragic situation and/or your desire to take in the girl into making a massive commitment he's not really comfortable with?
His not wanting to be there now suggests he doesn't really want this to be happening. Did he make the decision to adopt her entirely freely? I can't see why he would say yes, and say yes because he truly wanted to make this girl his daughter, if he doesn't want to be there right now.
Is/was your dd's biological mother his friend too? That you imply he's never met the child before suggests not.
If all this the case (and I'm extrapolating from limited information) then you need to cut the guy a LOT more slack for agreeing to parent your friend's child, upon YOUR wishes.That he's reluctant to come home now suggests that it is not something he wants anywhere near as much as you. He is hugely sacrificing to agree to this at all, and I hope you haven't pressured him into feeling obliged to do it, and that you're aware of how much you're imposing on him here.
Hand on heart, do you think he's happy about it all? He's already relocated purely for the sake of your career recently (though you clearly feel that it is you the move has been harder upon, and that he should make an extra effort to oblige you as a result). Is it all that important to you how he feels really?
If I have the situation completely wrong and in reality he has been massively enthusiastic about taking the girl in up until this point and is suddenly abandoning you now that it's become real, then I apologise so much for being rude above, and I'm a twat, and YANBU at all. But forced to draw my own conclusions from limited info,this is how it reads to me. You need to clarify these things before anyone here can give you a worthwhile opinion. You are very vague on the crucial details.
Wish all 3 of you the best in what must be a very hard time in all your lives.