Somebody did an analysis of his speech, and found that his vocabulary has markedly decreased in recent years. That’s one of the signal early indicators of dementia. Even back in 2016, he was noticeably more articulate. Since then, several other symptoms of dementia have shown up: Memory issues, doctors concerned enough to do cognitive assessments, losing the ability to process metaphors, impulsivity, uncharacteristic swearing, and losing track of the passage of time.