To believe in what man says is impossible you must first have faith that God can do the impossible. Faith is unseen you believe that it will turn out for your good even though in the natural it seems like all hell is breaking loose. The definition of faith is found in Hebrews 11:1 NIV "Now faith is confidence in what we hope for and assurance about what we do not see". Although the doctors said this disorder and disease is for a lifetime because their is no "scientific" cure for it. But God specializes in the impossible Luke 1:36 and Jesus Christ is a healer who's report will you believe?
I am going to put my faith and hope in God and in Jesus Christ the savior of the world that he can and will heal, rebuke, and cast out all and any disease, disorder, illness, or infirmity that is not like him. The devil is a liar and I refuse to except the lies from the enemy that tells you it is over for you, there is no cure, this is your life, you have to accept it.
Begin to increase your faith in the Lord Jesus Christ and receive the knowledge, understanding and will of God that it is his desire for all of his children to be healed, delivered and set free John 8:32, 36, Isaiah 53:5, 1 Peter 2:24. For according to Hebrews 11:6 NIV "And without faith it is impossible to please God, because anyone who comes to him must believe that he exists and that he rewards those who earnestly seek him".
If there is 100% chance your son or daughter could be healed would you not seek the Lord with a pure heart, increase your faith and believe so that God can heal your child?