If you are going to be upset about other people like this, you will be in a state of constant anger.
It’s not your responsibility to control what people do or think. My advice is to let those people be who they are, while you focus on being the best you can be.
Keep the people you vibe with in your life, and let the others go. Meet your grandfather and just observe him. This is life showing you someone who is hateful, from the sound of it. It’s just an example of who not to be, that’s all it is. Learn from that and remain calm.
You can do it. :)
If you are in the right state of mind, you can even smile at horrible things he says, because it’s just about him, not anyone else. You will start to view him as someone funny, like a child that messes up because they don’t know better.
Don’t fight people you don’t agree with. Just say what you think, and leave. No need to argue at all.