i would point out two things. first, we live in an era of people selfishly taking offence over the silliest, petty things. it's a shame to see this but it's real.

the second thing is that folks who have never dealt closely with alz/dementia patients have no real idea what it's like and how difficult it is. your friend really has no idea what you are going through. i was like that until my mother developed dementia in her late 70s. when my parents were 81 and 80 yrs old, my father went into the hospital and i stayed with my mother for 5 days. that's when i discovered how much i didn't know about the difficulties of caretaking for this disease. nobody who has never done it has no idea how hard it can be to explain a complex situation 50 times or more in one day. and the deal with my mother was that you had to explain it to her every time or risk her going into one of her rages. if she got angry, it was possible for her to, literally, stay in a rage for 2-3 weeks. hard to believe but it's true.

so after dealing with my mom, when my wife developed dementia, i at least had some idea of what i was doing. those of us who caretake for dementia learn skills and develop expertise that the rest of the human race never knows about.