Yes, the attitude is very normal for someone with encephalopathy, which he obviously has if he's taking Lactulose. I've never heard of anybody who does like Lactulose. You can try putting it in a drink that he likes, to help mask the taste of the Lactulose. It's very important that he take it.
Creatinine is an indicator of kidney function. Doctors are not quick to put someone on dialysis, even temporarily, so if they are doing so it is because he really needs it.
Try to sneak in some time for yourself, even if it's just a short walk or a bubble bath. It's important to remember to take care of YOU!
"But that was yesterday, and I was a different person then."
Alice in Wonderland, Lewis Carroll