My Dilemma

I don't have problems in life, I live pretty worry free, I got car insurance, gas, bread, chocolate milk and after that its just fun money spending time, but I do have situations I don't know how to deal with. Probably the biggest one thats been bugging me for a while is that my family calls my grandfather "Popo" which is a cute name my cousin gave him as a kid, the only problem is when I say the family calls him Popo I mean really just me along with the little kids in family. I can't shake it though, my older cousins stopped calling him that like 4 or 5 years ago and just call him by his name, "Dick", and I feel super weird about calling my grandfather Dick. My grandfather is the most honest man on the planet, but I'm still suprised he hasn't called me a sissy girl for calling him "Popo" at the age of 18. He is one of those who joined the navy too, so at my age he was being yelled at by people, treated like junk, and here I am saying"Popo is there anything I can you at the grocery store" first off treating him like an old man like he's not capable of going to the store himself and then totally sucking up to him like I'm his bitch. It just is bad and it constantly happens. It also sucks that I talk to my dad about him and since he knows I call him Popo he calls him Popo to make it seem like even the big boys call him that, bless his heart. I'm okay with talking about him with other people and calling him "Popo" because I know the women in the family find it acceptable, but I just feel weird. I dropped off some boat part to him and he was on his on his friends boat and when I was leaving I didn't know how to say goodbye, like I had to say something, he's my grandfather, but I didn't want to embarrass him in front of his friend by saying, "Bye Popo", but I also didn't want to say,"Bye Grandpa" and throw him off, so I just said,"HEY! I'm leaving".
I told one person in my family my dilemma and that person blew up. She started saying,"It's not weird I call my grandmother Grammy" I said,"well your'e a women" then she decided to go in this approach,"well what else you going to call him, Big Dick?" "no" "You can't call him Small Dick, that can be offending and you can't call him Grandpa Dick because then he just seems old......yeah you're right, you are in a Dilemma"