I don't want my grandpa to die on or around my birthday like I think he will.
That sounds strange. Is there a reason you don't want him to die around that time?
I want to enjoy my birthday without being sad about a death.
If he is dying then he has no real choice of the time that he passes. It's very rude and selfish to only think of yourself while this other person is passing away.
It is not like that. I love him a lot. I have to get through this.
Well you sounded kind of selfish. Like all you cared was about your birthday not your grandparents health or his death. People don't like people who are selfish and it might make them not want to be around for your birthday.