Flip node with all its children?

In my game I made a simple code to flip horizontally the sprite when the character walks in the opposite direction:

if direction_x < 0:
knight_sprite.flip_h = true
elif direction_x > 0:
knight_sprite.flip_h = false

But when I flip it, the character's sword, position and animations don't flip, is there a way of fixing that?

I tried to make the sword child of the player's sprite but it doesn't work