God desires his children to be healthy. He wants healing for us more than we want it for ourselves. God desires a relationship with us more than our healing.
Maintaining peace and joy during a crisis depends on where we direct our attention. Worrying takes my eyes off God, and puts them on myself and my circumstances, to operate in my own knowledge and strength. That robs me of peace and joy. Living moment by moment, however, trusting God’s provision for the moment, and being thankful for that provision, keeps my focus off my problem and focuses on the solver of my problem. This keeps me in perfect peace.