I don't think pro bono is the right term. More like on a contingency basis.
It wouldn't hurt to talk to a lawyer. A good lawyer would be honest and tell you if you deserve damages or if you just need to accept the fact that sometimes really shitty things just happen in life.
If he thinks you have a case, then he should work on contingency ie, get paid only if he wins. But if nan is right and you would have to pay the other sides costs if you lose, then the lawyer better be sure of himself before you get into it.
Either way, best of luck to you. Love and enjoy having your daughter. That is the best healing there is.