Gifts are NEVER taxable. A parent can give as much money as they want to anyone and the person receiving the gift never owes tax. Doesn't matter where the money comes from, as long as it's lawfully obtained.
The person that GIVES the gift is the one that has to account for things. A person may make a gift to as many people as they want, each year, in amounts up to $14,999, and not have to make an accounting for it. For any gifts in one year, to one person, that total $15,000 or more, the giver must file a gift tax RETURN with the IRS to REPORT the gift. Tax may never be owed. The total of the gifts you gave over your lifetime that you filed gift tax returns from is subtracted from your lifetime estate exemption of $11.4 million. If you gave away that much in gifts over your lifetime and you still had an estate to leave, then every penny of what you leave will be subject to estate tax.
Most people that do have to file gift tax returns never pay a penny of tax, because most people don't have estates that large.