I have guardianship over my mother who lives a nursing home. My sisters and I have bought everything since she has been there. Can we split the chec

It is not clear to what check you refer or what is the source of funds.  If it is your mother's money and you have authority over it as the guardian of her estate, there are two considerations.  First, you must get the permission of the court to expend funds to reimburse your sisters.  Second, you must get the permission of the court to reimburse yourself.  Please work with your guardianship attorney to file the proper motions and proposed orders approving those motions.