What kind of doctor should we take my verbally combative grandmother to?

I had the same worries you have about your grandmother. I asked around to everyone I could think of, my own doctor, community pharmacist, co workers ,ect.. and everyone suggested I take my mother to see a geriatric specialist becaused they are so familiar with this type of behavior. I brought a letter with me to the appointment and very discreetly asked the receptopnist to have the doctor read it before she came into the exam room. That really helped ease my mind and gave the doctor a heads up. Lucky for me, my mom was on her best behavior that day.. who knew??? However, I was glad that I got her in with someone who is experienced with people who can be cynical and combative.
Getting her to go was so stressful to me. I waited until the last possible moment to tell her and said that she needed it for insurance purposes. It worked. She still does not follow the treatment recommendations. She can not/ will not/ forgets to/ take her medication on her own. We now have a caregiver specifically for that purpose who sees her a few hour per day. She does not follow ANY advice about diet, exercise, socialization, home safety, etc... we just muddle through the rest of it.
You sound like a great and thoughtful grandaughter, Shelby. She is lucky to have you. Good Luck getting her to the right doctor.

Candy is right. Seeing the right kind of doctor is more important at this point than seeing someone quickly. Even if you have to wait a while to get Gramma in, holding out for a gerriatrician is your best bet.

Good luck.