My husband is 6 years into Alzheimer’s; I have read that there are different "levels" of dementia. Can someone please explain them to me?

Yupper - check out this article on the site. It talks about the different stages.

https://www.agingcare.com/articles/stages-of-alzheimers-disease-118964.htm

My mom says critical things to me even though i'm here to do all the work I can to help her. I don't know how yo take it anymore? Is this part of her illness or should I ignore her? Or just leave?

Yupper, I've read on this board where people say that the earlier phase of Alzheimer's/dementia can be more difficult for everyone concerned-- because the person with the Alzheimer's still has enough cognition to feel scared of this feeling that "something" is happening to him/her.----and that this can cause negative behaviors in that person. My father has some kind of personality dementia, and we saw this in him. Now that the dementia has worsened, his outbursts have lost some of their "steam." My sympathies to you as you cope with this difficult experience.