my life insurance will go to my grandkids whom i have custody, does gaurdianship of the children also mean the gaurdian control their money?

A guardian of the person is not a guardian of the property.  A guardian of the property is known in Georgia as a Conservator.  These people have to be appointed by the probate court in the county where the child resides.  The person has to meet strict financial requirements so that the Court will know that the person can be trusted with the child's money.