My 4 greatgrandsons, 4 & under, live in a filthy house with no decent food. All offers of family help have been refused, except to take the boys wher she wants to go out.Her boyfriend uses drugs in the house. Can I charge her with being an unfit mother & remove the boys until she gets herself together ?

Hey,

Yes you can. You can get in contact with your local dept of family and children's services and have them come out to her house to take a look around. You can also file for custody through your local magistrate court as well since you are the grandmother.

Not so easy. You can try, but there's no guarantee that anyone will even go look based on your say so, or give you custody.
And drug use would either mean them seeing it or a conviction for it, and without that and/or DCF saying that the parent and place are indeed unfit, you don't have much chance of getting custody.

Be careful, because although your heart might be in the right place, you don't want to be cut off from seeing the kids completely out of spite.