~ from email ~
All the teachings that you have learned about honoring God in all circumstances would apply. Many writers have produced works on this topic. Perhaps you may find some and see what you can glean from them.
However, I would add that you can pray for your son’s healing, while you continue to give him all the natural help that he needs with his condition. Of course, some church traditions tell us that there is no longer miraculous healing for us. But I spit on these traditions. This is a wicked man-made teaching, not remotely hinted at by Scripture.
There is no time to explain this in detail, so I hope you would consider this and pray that God may give you insights on the matter. While you do this, as I said, continue to give your son the natural help he needs.