How to deal with an unsupportive parent

I need help.

I have a 2 year old son, and my father has never wanted to be called “grandpa” or anything by him. My son doesn’t even know what to call him/who he is. He barely makes an effort to see us but he will text me every once in a while to see how I’m doing.

Now, I’m 4 months pregnant with twins. I haven’t told him yet, because I want to be happy about my twins and pregnancy but I know he is not going to be. He didn’t want one grandchild, and now he is going to have three.

Has anyone went through this? Do you ladies have any advice/stories to share? I would love to hear from others in similar situations.