Hi I was reading your post when I instantly thought of my brother, he has a condition (sorry can't remember the name, but it start with an E) that is his liver doesn't filter his toxins properly, therefore effecting his brain function, he goes through stages of where you can almost call it dimentia like, i would speak to your husbands doctor about it and possibly get tests ran for that, as aneurysms don't tend to show symptoms unless they have rupturesv/ bled.
I myself had an aneurysm clipped back in April 2011 and never knew I had it until i had a head trauma accident and had to have an MRI.
But back onto your husband, I really feel that you should speak to the doctor about the toxins not being filtered properly, my brother can go from normal one day to thinking he is drinking something and there isnt even a glass in his hand, to sleeping all day, can't hold conversations, just some real weird stuff at times, but when his medication is working and his toxins filter correctly he is like the brother we all know and love,
Good luck and please keep us up to date
Take Care
Nelly