Having just been through this with a neighbors goose, I think your gander would be happier with another goose for companionship.
Our neighbors gander lost his mate of 6 years last summer and was miserable. He honked, called, wondered around all hours of the day and night (looking for her??) for weeks until he finally wandered over to our house one day and discovered we had a pond and ducks. He's been "visiting" with us every since.
We tried for months, without luck, to locate an adult female for him. Eggs for this breed were easy to come by so I finally ended up purchasing an incubator, some eggs, and hoped for the best. It's been about nine weeks since those eggs hatched and the babies are now living outside with the gander. Besides being a little over protective of the babies, the gander is much happier.
When we first started introducing the babies to the adult, he wasn't quite sure what to think of them and kept trying to attack the male gosling. Even though the goslings were only six weeks old at this time, somehow he knew the other two were females and was literally captivated just watching them. After two weeks of letting them interact through fencing we were able to turn the goslings out with all the other waterfowl and everyone is getting along just fine.
Now, if I can only figure out how to get the neighbors gander and his new gosling friends out of my pond and back to their own.