Don't bother, if you're in a position to do so, help them find a first-class brain surgeon. Get them into Sloan Kettering, Mayo, Duke or OHSU or whoever. Help them look for clinical trials to get chemo past the blood-brain barrier (I've heard some promising things in this area, though I'm not sure if it's being tested on humans yet). If they have a family that's taking care of them, offer to help them. Even just a gr…
See the problem with this disease is that the general treatment is shit. With two inoperable tumors the chances that chemo and radiation alone do anything more than giving him a week or two are zero. So in that respect, going to a first-class brain surgeon is no less a moonshot than any other bio hacks I can find online. You're just recommending the "most-accepted" moonshot.
American "physicians received significantly less intensive care than the general population" at the end of their lives [1]. (Canadian physicians "used both intensive and palliative care more than nonphysicians" [2].)
The lesson seems to be yes, go ahead and pursue your moonshots, but don't let that cloud the reality of the situation and don't let the moonshots debilitate what little time you have left.
[1] https://jamanetwork.com/journals/jama/fullarticle/2482318