There are no scriptures that advocate for or against such "medical" preferences. It all comes down to an individual's fear of certain situations and their trust in the Lord. Perhaps telling a person that Jesus loves them and that He works for the good in all who believe would be a better approach. To each is given a certain measure of faith according to their belief that God is sovereign over all things and in all things. The Holy Bible is filled with ordinary people who overcome extraordinary circumstances through the power of the Almighty Creator. Besides, getting sick is most often just a temporary discomfort. God decides when our time has come and our faith in Him translates to our fear of passing from this world. We fear things for fear of punishment. If we are made whole in Christ, their should be no fear of leaving this world; for perfect love casts out fear.