May Allah cure him.
Your dua to Allah as a parent and someone in distress is more important for him than any other individual. Do not be desperate or feel despair as this is a test for you and you will be rewarded for your patience.Try to read Ruqyah daily on him. Please watch this:
https://www.assimalhakeem.net/w
http://www.youtube.com/watch?v
http://www.youtube.com/watch?v
http://www.youtube.com/watch?v