Dementia

I found out today that my Grandma has been diagnosed with dementia... It's really breaking my heart. I lost my grandpa last June to a heart attack, it's been very hard to cope with and a huge shock for my grandma. She's only 76 and my god I love her so much and I can't stop these tears. Her doctor is giving her medication tomorrow and it will either keep her the way she has been this last year, which isn't bad a little bit forgetful but still my grandma, or it won't work at all... I'm not sure of the name of this medication but has anyone had any family experiences? With meds and how it has worked? I know not everyone is the same but I need to know to give me a little bit of hope! I'm trying to stay positive but it's hard, I'm so scared she'll forget who I am and have to move to a nursing home. I'll appreciate anything. Thanks guys!