bianca.......we must get our terminology straight here:
Melanoma is usually non cancerous, but may become malignant when it is then called Malignant melanoma.
Malignant melanoma can spread locally or recur after local excision and skin grafting has clearly happened to your husband...............this is NOT metastatic melanoma.
The original growth may then spread to lymph glands and even to lungs and other far away organs when it is then described as metastatic melanoma.
The treatment is far too complicated to discuss on AB, but I would guess that your husband has had lymphograms and whole body scan to rule out distant spread.
Has that helped?