I posted this earlier, but you can read the Virginia test for insanity
here; the relevant section is on page 1.3. Notably, this document states that in Virginia, "whether (the defendant believed) that act was morally justified"
could be sufficient to qualify Chris as insane. So if Chris thought raping Barb was God's will, an act of divine healing, etc, (which is exactly what happened) then it's certainly possible for the court to find him legally insane.
However, the court is under no obligation to do that, either. It falls on the judge or jury to use their own best judgement and decide if the fact that Chris thought he was carrying out God's will when he raped his mom, demonstrates legal insanity; they could say "yes, Chris was insane", or "no, he was not insane", as both outcomes would be covered by the facts of the case and Virginia law, and there is really no way to determine which way it would fall, outside the conscience of whomever gets tasked with rendering a verdict.