There are virtually no syndromes and/or diseases that are not reversible. If you are interested in taking control of your grandson's health [and I sincerely hope you are], the following will give you all the information you need:
Any of the discourses by Luigi Cornaro (available free online);
Any of the books by Horace Fletcher (available free online);
Any of the writings of Arnold Ehret.
Just like virtually everything else in life, it is all ultimately up to YOU.
You have all my best wishes for a successful journey and resolution,