I may have a very different relationship with my mother who has hypothyroidism. Every time she gets snappy, I snap right back. I fight every point that I can because every one that I win is one more that she is doing. When she tries to turn it back on me, I turn the argument back to her with something along the lines of ‘I’m not the one who needs to take synthroid every day!’
Does it hurt? Absolutely! With my mom, whom I love dearly, by the way, tough love is the only way to go. That approach may not work in your situation. Just like the same approach does not work with every patient you have. Some of them need a soft shoulder to cry on and some of them need the authoritative voice.
You have to figure out what works for the two of you. This is not an easy road, but you will get there in the end.