But does God get to rejoice in the misfortune of God's enemies?
Rabbi Shai Held
The ideal and the best case scenario is for the wicked man who is ill to have both his body healed and his soul transformed. When that seems impossible (say, because the person in question has a truly intractable personality disorder), then I think it best to pray that Hashem do whatever Hashem deems necessary to prevent the wicked person from enacting his wicked plans, or from (further) damaging and endangering others. We should not dictate to Hashem the means of salvation Hashem will use; we should only pray for the salvation and leave those decisions in God's hands.
But also? People sometimes have emotional responses to things, and they need to work their way through our systems.