The question is does being a Christian immune someone from sickness? Does sin leads to sickness? Can God heal all type of sickness? If God can heal all type of sickness; why do some Christian die in sickness?

Sickness is one thing that no one ever wish to experience in life, ironically, it is one thing that no one will escape as far as this life is concerned. Being a Christian does not mean we can't sick. It will come, but how you handle it determines whether it will stay or go immediately. Yes! sickness attacked everyone but it does not stay in everybody, so stop welcoming sickness by your behavior. God perfect plan for man at creation was that we shall not know any form of corruption, but with the fall of Adam man knew corruption that has bedridden us till date. 

So long you are still on earth, you will sick when the enemy attack your health, but the good news is that God is able to heal you and will heal you if you believe. God is still in the business of restoring health to men (Jeremiah 30:17). In fact one of the best way to preach the gospel and to draw men back to God is in the healing ministry. In fact Jesus ministry and the apostle were dominated by healing from sickness (healing of the blinds, lame, fever, raising the death etc.( (Matthew 8:13; 9:29; 15:28; Act 3: 5-7; 5:1656).