1st of all, You are not responsible for this. All you did was open your home to your family. Not your fault!
I know you feel the need to fix it, but your plan is not a good one. It will put your grandfather even more inthe middle, cause him more grief and pain, and push your father further away.
The only solution to this is to get to the root cause of this hateful mans issue. That may not have anything to do with you or your wedding. It could be mental illness. It could be dimensia. It could be a whole lot of things. Or it could be a simple misunderstanding taken way too far. Maybe he was slighted somehow. Who knows. If it only affected you, I could see how good riddance would be a good idea. But, now that it's affecting other people, I think I would try to get to the root.
Go see him. Take an olive branch of some sort - like a box of figs or something that yall used to love when you were little. Reach out. Go with an open mind and openheart and try to understand what the problem is. Once you know what is wrong, you will be in a better position to deal with it. If he's truly hurt - apologize. If he's just unbalanced, talk to uncle and grandad about committing his mean behind. If you tow can't come to any understanding, then lobby on behalf of your grandad and uncle. ONce you've done all that, it's really out of your hands.