I am in the same boat as you, unfortunately. My parents are in their eighties, and in very poor health.
One big reason why I transitioned is they never treated me well even though I spent my whole life, until I was 46, trying as hard as I could, to be the boy and then the man they wanted me to be. I suffered a lifetime of psychological (and some physical when I was little) abuse.
They lionized an older cousin they took in. They doted on my younger brother and sister. I was a throwaway kid.
So I strip the nail polish, ponytail my hair, and wear baggy T shirts and sweatshirts when I see them.
Dad had a stroke in 2009 and has been in a sub acute facility ever since. He always was a whiny, passive aggressive creepy stalker kind of guy. If the stroke had not robbed him of speech and mobility, he probably would have harassed me out of transitioning. And he tries to stare at my crotch if I wear skinny jeans under my T shirt or sweatshirt.
Given that my whole life he was pressuring me hard to date, marry and have children, I think he knew about me even though I spent my whole life trying to hide it.
Every time my wife even mentions my long hair, he gives me the bad eye.
So no, I can't come out to my parents. They never loved me when I tried to be what they wanted, and they will never love me for who I am.
Hugs, Carly