Dealing with Delusional/Uninhibited/Hypersexual Behaviors with Dementia?

Hey there. We currently care for my grandmother, who has dementia. Since her last stroke, she's become absolutely infatuated with finding a man, obsesses over anyone who gives her attention, no matter how innocent (doctors, nurses, neighbors, church members, etc) and has delusions that the other party is actually obsessing over her. She always feels that it is actually we, her, caregivers, keeping them apart, and is pretty resentful about it.

She's 76, and consistently seeks out the attention of younger men who are extremely age inappropriate (between 20-40), and when they are nice to her, it seems to reinforce the delusion of her own sex appeal. While this may sound harmless or even humorous in theory, there are some serious, but delicate boundary issues in play. The people she comes onto are members of the church, the friends of her grandchildren (she actually put her tongue in the ear of my brother's 21 year old friend recently, leaving him feeling pretty violated and confused), and even distant family members. She really has no boundaries, and it's incredibly awkward for all involved. And when we attempt to address the behavior as inappropriate, it only reinforces her delusion that she and her victim of choice are star-crossed lovers, that the family is trying to keep apart Romeo and Juliet Style. The worst incident, however, occurred last month when my grandmother (on the other side) passed away, and she started coming onto my grandfather at the memorial, as he was a newly single man. She's been asking about him ever since, which is pretty rough on my still grieving family. It's very upsetting for everyone involved, and we're really struggling to educate ourselves and find the best possible way to deal with her behavior.

I'd welcome a response from anyone who might better understand what is going on, or know some helpful ways to address/minimize it. Any feedback would be greatly appreciated.