living with Grandma

Hi! I'm am 18 and currently living out of state with my grandma. We are at my parents house that they just bought 2 months ago. I am taking college courses but only 1 is an in person class. My grandma is only 74 and see we have been down here for the last month is very depressed. I trying getting us to do stuff. But she rather just watch tv and stay in bed. When my parents are here she is up and moving as an act. I don't know what to do. At her other house she is very active with friends but she doesn't know anywhere here. It makes me upset cause I can keep busy throughout the day and she just sits there upset. Please help this is making me upset.