Torsion Rod Adjuster Stuck

With it already snapped, you can separate the lower ball joint to release some tension and then carefully cut the torsion bar and knock it out. Be careful to stay clear when cutting the bar, as there can be significant movement once its cut through.

You are already destined to use replacement hardware because of the broken adjuster. If you are careful, can use heat and vice grips to remove the broken adjuster. Be sure to clean and chase the threads and then use anti-sieze or moly grease on the threads to avoid a similar situation years down the road.