Maybe, but that will still be very hard. After the collision a lot of the debris will still be moving at a speed and direction comparable to the asteroid's orig

Maybe, but that will still be very hard. After the collision a lot of the debris will still be moving at a speed and direction comparable to the asteroid's original trajectory. Because the asteroid will have the greater mass, you'll find it'll be the net exporter of inertia into the impact mass. On top of that, making the rendezvous at such an extreme difference of speed will be very difficult.