Perhaps there is a charity which Mrs Stewart was supportive of. If so, could the club perhaps set up a justgiving site specifically for the club's fans to contribute in her memory? Obviously the wishes of Tony Stewart and the family are paramount in this respect.
Sincere condolences to the Stewart family.
Love and sympathy to the Stewarts, their family and friends.
Sad news indeed. Condolences to the family, my thoughts with them all.