Can a notary in nc notarize family documents?

Most jurisdictions do not explicitly forbid notaries from notarizing signatures for family members, as long as the notary does not benefit thereby (in some states, notaries' fees are set by statute; this is not what is meant by "benefit"). Notarizing a will in which the notary is named as a beneficiary is at the very least suspect, though.

Depending on what the document is, it may not really matter whether the notary is related to the signer or not. If you're just having a signature on some routine paperwork notarized, it doesn't make much difference whether it's done by your third cousin or by a complete stranger.

Any notary should be familiar with the restrictions on what he or she is or is not allowed to notarize, so if there's any question in your mind, just ask. If there's even the slightest irregularity about it, most notaries will err on the side of caution and suggest you have it done by someone else.