Did you know that some of the 75 feet versions of N-Strike Elite was shipped in the Phillippines? You might not agree, but I got one. That's my proof! So, should we report it to Hasbro or not? Pls. comment.
Then return it! There's nothing else we can tell you. Even the pros cannot trick airport security. I highly doubt if a bunch of teenagers on AG can come up with a way for you.
Send it back, mail it to your home, or try and smuggle it on the plane. You only have three options. Pick one and hope for success.
All that matters is that you are transporting it safely under TSA standards
You do realize he is in the Philippines, right? I don't think the TSA will be over there.
They have no way of knowing if it's not an international version, or what the range is, and they don't care.
It's Illegal in the Philippines. That's where the problem comes in. Who knows how strict they are about Nerf guns over there, they might confiscate it and give him a hefty fine, or they might not even care, but why risk it? I would just mail it to myself. At least the chance of success is higher.