Is a power of attorney allowed to deny visitation for personal grudges they hold against you?

Asking for someone's SSI check for allowing visitation Is illegal. This is government money. Your DAD needs to get help. It's his mother.

One point your cousin does not seem to understand at all is that a POA is only valid while a person is alive. Once the person with a POA document passes away, the document is immediately null and void. Your dad needs legal advice as laws regarding family contact and trespassing vary from state to state. If he truly wants to see his mother, it would be worth spending a few hundred dollars to sit down with an attorney for advice. Good luck!

I assume your grandmother lives with her granddaughter, your cousin? I suppose if that's the case the trespassing could be a factor. If area on aging can't help, you might go to your county judges office or justice of the peace and discuss it with them to see if there is a procedure in place. Perhaps a sheriffs deputy could meet your dad at the home and see that he gains entry. Similar to a domestic violence case but proactive. Is your grandmother an invalid? Is your dad? Be careful to not get caught up in accusations on social media etc that can escalate the problem. That's very stressful for your elders to listen to and can inadvertently give ammunition to the cousin. Less talk and more action with seeking help from the resources available. I hope they get to visit.

A POA doesn't make a person god! No it's not legal. They have authority over bills paid and financial legal things. Not who sees who on visits. She's overstepped her role. Get some advice that you can use to back up any decisions.

Of course it isn't legal. But that is not stopping her. It may take a court order and police enforcement to change her behavior. I think I would start with calling Adult Protection Services and explain the situation. You don't have to get into all the drama of the reason for the grudges but that relatives are being prevented from seeing this vulnerable adult. They will investigate. That may not be the end of it, but I'd start there.