Technically, your grandmother's home is not your responsibility, it's your mother's. You have no obligation to help her unless you said you would, and even then you really don't have an obligation.
I'm going to assume you haven't told your mother you'll help, in which case I would tell your mother, the next time you talk to her, that no you will not be helping her with her mother's things, and that she should hire a moving company. I also would not offer her money to help with expenses. Again, it's not your responsibility, and that could put you in a position where your mother will continually ask for money on this project as a way to get you to help.
At 37, your life is your own, and you don't have to do anything you don't want to do. So follow your gut instinct, and tell mom sorry, you'll have to help yourself on this one.