Move arms along with camera angle (on the Y-axis), but keep regular animations possible?

Is there any way to make it so that the arms follow the camera angle (on the Y-axis), but keep regular animations possible?

Like if you weld the arms to the head, you can't manipulate the motor6ds of the shoulders anymore, so therefore you cannot play any animations.

I've tried a lot of things but nothing either it doesn't work properly, or I can't use animations anymore.

I do know how the find the angle of the camera angle though:

local CameraAngle = math.asin((mouse.Hit.p - mouse.Origin.p).unit.y)

Any help is greatly appreciated. C: