My CPA just told me that I need to file a IRS form 709 every year I make a gift into my nephew's 529 or UTMA and that even parents and grandparents must do so of gift taxes will apply.
Is he crazy or is this true?
Your question isn't exactly clear.
Are you asking "OR gift taxes will apply" or "IF gift taxes will apply"?
While it never hurts to do research and educate yourself, I strongly suggest you take the advice of your CPA over random people on the internet when it comes to gift tax returns. If your CPA is suggesting that you cover your ass with a gift tax return, then you should probably cover your ass with a gift tax return. He knows more about your gifting situation than we do.
When it comes to gift tax returns, if he's right and you do not follow his advice, not filing a gift tax return can have serious consequences. If he's wrong and you do follow his advice, then the worst that happens to you is that you filed an unnecessary gift tax return.
To be honest, even if you provided every detail here, I would not personally want to offer advice to you about gift taxes. It's an area of tax law that is fraught with liability and complications. If you want a real second opinion, then hire a second CPA.