Bruce Willis, known for his roles in "Die Hard" and "Moonlighting," is battling frontotemporal dementia.

Friend and director Glenn Gordon Caron has been visiting Willis monthly since the diagnosis.

Caron believes Willis still recognizes him briefly during visits.

Willis, once a voracious reader, has lost his language skills.

Despite these challenges, he remains recognizable as Bruce.

The disease has taken away his joy for life.

1. Caron first worked with Willis on the "Moonlighting" series.

Willis was known for his exuberance and love for life.

The diagnosis came shortly after he stopped performing due to aphasia.

Frontotemporal dementia affects brain regions, causing personality and behavior changes while preserving memory.