Help thou my unbelief

A Father with a demon possessed son, who has been seeing this for years, the pain and anguish. The physical harm, the attempts to burn in a fire, the drowning attempts, for years he has watched this. When Jesus asks what do you want he says whatever can be done. He didn't ask for a full healing, he did not ask for the moon, he asked for whatever Jesus could do. Jesus says if you believe all things are possible. The man can not believe it can be better, he has spent too many years with this situation, too many years of heartache and pain watching his son. And he cries out Lord help Thou my unbelief. He wants it so much for his boy yet he is in a cold reality of pain and misery.