That is good of you to offer on of your Bendix hub for your buddy 27inch . I hope your buddy comes to his senses and realizes that he has limited choices. If he had to pay for the Bendix it would be even more expensive than the new Shimano hub.

You could perhaps find a Shimano knock off coaster brake hub and if he looses interest in the bike quickly, that will avoid the possibility of a hub failure or rebuild. I heard that Shimano rebuild kits fit these hubs.