There are two types of dependents, "Qualifying Children"(QC) and standard ("Qualifying Relative" in IRS parlance even though they don't have to actually be related). There is a requirement that a QC be closely be related. Only a QC qualifies a taxpayer for the Earned Income Credit and the Child Tax Credit.
The boyfriend could only claim the child as a Qualifying relative and then only if he lived with the child all Year (because the child is not related) and if he provided most of the child's support.
