Pikachu - my condolences on the loss of your grandmother. I'm sorry about your cousin's refusing to put you up - it must be awful to have the emotions generated by that on top of your grief.
Maybe you can use the money you were going to spend for going to the funeral to visit your grandfather later. With not having to travel at a particular time, you'll probably be able to get some really cheap fares that might make a trip possible.
It would have been nice if your cousin had called you. She might have told you no for reasons that wouldn't have mattered to you (a messy house, the fact that you'd have to sleep on the floor) - information that might have come out in a conversation.