right-wing brain rot
Theory that as the brain ages it begins to rot away, thus giving way for people to hold more right-wing beliefs as they get older. As right-wing beliefs are inherently nonsensical only a poorly functioning brain could hold them.
Oh, he used to believe in science and factually correct information, but unfortunately right-wing brain rot has gotten a hold of him and now he thinks science is out to get him and extreme weather is the result of gay people having more rights.