This simple shift in pronouns can improve cooperation and lift your loved one's mood: Use "I" statements" instead of "you" statements. "You" statements are those like, "You don't make sense." Compare that to "I" statements, which switch the emphasis to your abilities and make the person with dementia feel less criticized and ineffective: "I'm sorry, I'm having trouble understanding you."
Instead of . . . * "Don't you remember I told you to be ready at 3:30?" Try . . . * "I'll remind you just before 3:30 when it's time to leave."
Instead of . . . * "You just said that." Try . . . * "I'm glad you told me that."
Instead of . . . * "You don't listen!" Try . . . * "I came up with a good way for us to remember."