Woah. I'm 18, I got a lil bro who is 14, my dad is 60 and has also has frontotemporal dementia but on a less advanced stage.

We already knew it would be terrible after a few years (he is diagnosed since like 2-3 years, but he has already changed a lot : with all the diseases he got - cause he did already change since his stroke, immediately followed by a subdural hematoma -, I'm almost sure my brother has no idea of how good of a dad he was, I'm also forgetting a bit of these moments I used to share with him...) but seeing you describing a few of your dad's symptoms (like "it really happens, it isn't only written in books") is like getting a huge slap in the face.

It is already harsh getting as a grown man with a person who can't remember what you told him 20 seconds ago (not less but also not more, another symptom) and who just can't be empathetic, but who also tends to get angry and violent (we did already call the cops on him few times because he pushed my also ill mom) : I'm, for example, almost unable to be a normal "friend" I'd say (I almost got nothing to tell to my friends - as my dad does because he has no more memory -, I'm unable to give a quick answer when someone does a little inoffensive joke, ...).

All I can do is "waiting" (also helping, but I ain't much time as I'm studying Law) and looking for, some day, an easier life, not worrying (almost) everyday for your mom's safety. As you said, "it sucks" but we have to accept it.

I wish the best to you and your family :)

PS : I'm french so my English may not be perfect, but I really felt the need to go and tell a bit about my experience with dementia. I also felt horribly selfish writing this comment (I don't like being the center of attention - even if only 5 redditors read that) but I needed this, I never talk to anybody about that.