Sounds like you are having quite the time. What you say really is so true "but if there is anything I’ve researched about this disease is that you can’t put it in a box".
Some docs try to do that.

I wan to give you some good info on the testing. I have to look at the notes. I will get back to you in a separate post.

What you are seeing with the behavior is unfortunately something that isn't uncommon.
Right now I am at the semi paranoid stage where I feel like everything is argumentative putting me on the defensive and acting like a 2year old sometimes with my reactions.
My hallucinations aren't nearly that bad, but it can definitely happen.
I thought the same thing as you di on the doc saying 50% don't. I immediately thought 50% can. That is saying it helps someone not some Duh.
The good days and bad days are part of it. Somedays - even a week I will be doing pretty well. Then back to Lewy land.
Wow - the inability to have conversations with several people. Sometimes too much to process, too much to follow and frustrating the you want to chime in but don't know when to jump in like most people. Then I get frustrated because when a break comes the conversation sway beyond what I was thinking or I forget all together.
Many of the bad day stuff you mention is true with me.
drooling, choking on food (not too prominent), staring spells, slurred words, quiet and withdrawn, night sweats, a significant loss of executive function.

Home health services are a real help. We found that the occupational therapist helped a lot to "Larry proof" some parts of the house. And customize some ADL's to help me with things such as taking the right meds at the right time, showering ( I forget to wash hair, maybe use soap or miss parts of my body).

Has he been tested for REM sleep disorders? It isa common thing that might be a contributing factor to the falling out of bed and yelling out in his sleep. I have RSBD (REM Sleep Behavioral Disorder) - again common with this.
This causes me to roll around in bed and it looks like hurricane hit the bed in the morning because I have thrash around a lot and the cover and sheets are anywhere but where they should be.
They can give him something to help with sleep and get into REM sleep.

You will definitely benefit from a multi pronged arroach with a psych and neurological team who work together.