My daughter is having a baby with her boyfriend. They are not married and have no immediate plans to do so.

There is no requirement that the baby have the father's last name.  Some use hyphenated names. I find that most of the judges will order that a name be hyphenated if the dad acts quickly and asks that his name be put on the birth certificate.  But your daughter wiill have complete control over the birth certificate.  In order for BF's name to go on the birth certificate as father, mom and BF will need to sign an Affidavit of Paternity.  The hospital should have a form.  If not, it can be found on line.