Not to sound negative but I doubt your husband would get sponsored from the UK in the current climate. Construction projects have dried up considerably and companies can hire local easy enough. The boom days are unfortunately over for now. It's not easy trying to find employment without local experience also.
Personally, if you qualify, I'd go the PR route. I think a CSCS site supervisors gold card would only be the equivalent of an AQF level 3.
Best of luck though. Hope I an proven wrong