An healthy Akita who's used to be outside will be fine in negative temps with shelter. I don't force the issue with my huskies who prefer to be outside until it's -40 or lower. They've never had an issue! I have found that most of them eventually decide inside is nicer anyway...usually after the first time the try out a couch!

Blankets will just get wet. Straw is much better bedding. Shove lots into the house & he'll make himself a toasty little nest!