God I hate the dramas in my life?

I know I’ve been a little annoying child lately..well see what’s the new toy that I can’t get..
In case to help you guys catch up, I’m a gay in China, where there’s still general discrimination. I came out to my parents last year and they told me they still love me and it’s okay to be myself. Mom says it’s fine if some of her workmates know (which they haven’t yet), and dad still got a little pressure, which is beyond what’s in my wildest dreams.
Here’s the little stupid cute thing: My gaydar just shouted on my grandpa, this little old man who has loved me deeply throughout my life, who, on the other hand, my dad’s always been discontented at because he grew up surrounded by the complaints on the old man from my grandma.
I still love him, for god’s sake, and I think it’s not that necessary to blame him for not being a good husband just because my grandma’s words. It’s their relationship, after all. But I just wanna make sure here, is telling my father about this a horrible mistake? (I haven’t yet.)
My grandma has been complaining about his bad temper for decades but I’m not sure if she knows. They don’t know I’m gay, either, and as a matter of fact, my grandma’s alzheimer’s disease is getting slightly bad.
God..