I have read about the "rules" online and have actually been chastised by family members when I said things that even didn't elicit a negative response from the patient!

What I found is best is look to the "real world" professionals who interact well with those with dementia patients, listen to others (including family who don't always get it right) but then make your own best judgments. I found that that worked very well.

I found that what I read online from authoritative sources proved to be mostly not applicable in my situation. For example, contradicting the patient. I did it and it was like contradicting anyone who is not correct in something. No problem at all, just like you found.