[quote=Narutopedia]The Eight Trigrams Sixty-Four Palms is a taijutsu that should only be passed down in the main house of the Hyūga[/quote]

I'm going to classify it as basically a Hiden. It's use is not common knowledge and it has to be taught. With no examples of someone using gentle fist in Canon aside from the Hyuga, you cannot contest it.

Being Main House is fine, but the character would be 4-10 at the time, especially if his parents were part of the resistance. He's not going to be able to learn the 64, which is a Hiden, and he'd have to be a Neji-level prodigy to do so on his own.

The character's age, conveniently, should only be 11-13, which means that he still would be below Hinata based on the fact she received formal training and still was not on the level of Neji.

That said, Juken is still very powerful without the sixty-four palm. I see no reason he couldn't just do a sixteen palm variant. He could also use palm thrust and a watered-down version of the vacuum jutsu. I'm not saying he can't have the core components of the jutsu, I'm saying it isn't viable for him to have the full extent of their abilities. They were, quite obviously, used to show how Neji was a prodigy.