If it were me I would absolutely do at least lots of curcumin (wonderful against brain cancers), oleander, colloidal silver, N-Acetyl Cysteine (an absolute must for glutathione levels), iodine and plenty of natural sunshine (which he likely gets at his job). I might also strongly consider DMSO to help get things past the blood/brain barrier and open up the cell membranes so the good items can get in and the bad ones more easily get out.
I think you are right - if allowed to they will eventually find a way to kill him.