Best thing would be to buy some Isotoner driving gloves with Thinsulate and a good rubber kitchen glove over them. I have found them good to 0 C at keeping my hands warm, but I can also reach into my pocket and get my keys out and separate them without taking off the glove. Then either some large rubber gloves to protect the glove from moisture or regular surgical gloves you can buy at a paint store if he wants maximum dexterity. The surgical gloves are of course use once then throw away, but a box of 10 is like $2.50 and I would imagine the best way to go as being near a knife a cut or abrasion is bound to happen sooner than later.
I'm still alive Ray and out of the ICU, but not home yet.