coach's interference

[NavyCoach]

There is an over throw at 3rd base. The coach moves to get out of the way. The runner heads for home. The 3rd baseman picks up the ball and starts to throw it home. The coach had moved to get out of the way of the loose ball, but is now in the way of the throw. The 3rd baseman bumps the ball twice and them moves to his left 2 steps and throws home. The runner was called safe. Is this coach's interference or does the player need to throw and hit the coach to make it interernce?