Covering his ears will not help the situation.....They need air to breathe....If this is yeast infections, then even more so....Ear problems in dogs are normally food related....A low quality food full of grains could be the problem....
A rare infection that was never cleared up the first time, is possible also.....
The best med there is for ALL kinds of ear problems is called, "Zymox".....Can be purchased online without a prescription....Safe to use, too!!!! Let us know.......Karla
My first thought is that ear muffs or head coverings might be a bad idea, as even though it's cold where you live it is wise to have air able to circulate in the ears, to prevent ear infections.
But if actual frostbite is possible because of severe cold, then I guess that is different.
I have certainly seen hooded jackets for dogs, where there is a fleecy collar which comes up over the back of the neck and the back part of the head. You could maybe check those out online? You could google "hooded dog coats" or "dog jacket with hood" etc.