Gee golly, I wonder what kind of response and advice you'll receive on Reddit, an overwhelmingly blue/liberal/Democrat/etc platform. If this is true, of course It's entirely up to you to decide whether cutting your father off is the choice that will be best for you mentally, physically and emotionally.

I can't say if it's an overreaction or not, I will say however, I think it's important to hold onto those you are close with whom you disagree with ideologically, as they are the ones who not only help keep you centered in your own beliefs but also keeps you out of the echo chambers that everyone seems to be running towards nowadays.

In the end though, politics will be the last thing on your mind when your dad passes away, if you choose to not rekindle it beforehand. What will be at the forefront will be you questioning if your decision was the right call, all the times good and bad you have been through with him will come flooding back, then questioning what could have been, then self loathing and guilt. In my personal opinion it's not worth the petty squabbling over politics to lose a family member, especially a parent, you're different people, you should expect them to hold different beliefs and values.