Jimmy is right. Under Federation rules (High school, except for Texas who does not follow them) a FG follows the same rules as a punt.
The holder can have his knee down so long as it is a kick formation (7 yards back). This includes for a fake. This only applies if he receives a snap directly.
However, once the ball is kicked it is now a new play rules wise. If the ball is away, it's treated as a punt (which can score points), if it's blocked, it's a fumble...or just a shitty kick, it's a fumble.
Since on a fumble the holder does not get the ball directly (it isn't snapped to him) he is down once he picks up the ball.
This according to a coach on staff who used to officiate.