history: My grandma was very sick and unable to get around very easily. I decided to go stay with her so that I could take care of her until she was better. My grandma was very sick and unable to get around very easily.  I'm sorry to hear that. Is there anyone who's there to help her?
current: No, so I decided to go stay with her so that I could take care of her until she was better.
next: That was nice of you.  My parents did the same with my grandparents.  She's very fortunate to have you.