I'm sure others will be able to help you more, but I can say that yes, she's acting normal for someone with those conditions ---if there IS a normal for it! It could get worse, with alzheimer's they can/do forget to get dressed, or have a habit of taking off their clothes (my grandmother). She can do a LOT for someone her age....be thankful for that. My grandmother couldn't dress herself or feed herself. If you want to do something to make her last years happy, then if she wants to eat straight sugar, let her. She'll die happy. She may or may not know what's happening.....The hardest part will be not getting mad at her. She can't help what she does. Yes, my grandmother went thru a mean streak. She also hid things and then would call the police and have them come to the house saying she'd been robbed. I would suggest that you DO go to town, let her get upset. YOU need to take care of yourself, too. She'll either keep getting upset or she'll get used to it.
I'm with the other that said do some research on both diseases here on the Net -- and talk to the doctors about finding you some help. The local Senior Services dept for your state might be able to help you.
Best of luck! {{{HUGS}}}