Sadly Bruce has now been diagnosed with dementia too. https://variety.com/2023/film/news/bruce-willis-dementia-aphasia-retire-1235525599/
This is sad. Frontotemporal is also, like, the worst type of dementia for the patient to suffer. My maternal grandfather had it.
With Alzheimer's and a lot of other types of dementia, the sufferer is rarely aware of it, and usually only at the onset of symptoms, early in the disease. Alzheimer's patients are mostly pleasant, just prone to confusion and may have bad reactions to that from time to time, but even those episodes are forgotten and they go about their day. It's slow and terrible, but it's not really until the very end that the patient truly suffers.
With frontotemporal, the underlying knowledge of dementia is there, and the personality changes are permanent. Perfectly nice people become raging combative monsters, and then realize it for a bit, but ultimately know there is nothing they can do. This is on top of the aphasia, which is one the most frustrating things in the world of medicine, and comes in two flavors: Expressive and receptive. With receptive, imagine your friends are having a conversation in a completely different language, except you took that class in high school. You know some of the words, but have no idea what they are saying no matter how slowly and clearly the pronounce it.
That is bad, but imagine the reverse (expressive). You are speaking perfect English, but the words coming out don't make any sense to your friends. They can also identify the words and know what they mean, but you aren't putting them in any order that they can understand. You keep saying "I love barbecue and beer," but they don't know why you just said "Pelicans biting California is fine for now, thanks."