This was taken on Evergreen Lake last December 24th. The person pushing the wheel chair was on ice skates
As Roadkill said, shouldn't be a problem on most lakes. I know when I've been on Georgetown, Williams Fork, Chatfield, Elevenmile, Granby (in most spots) there is some relatively smooth ice - keep an eye out for the ice boats or the ice wind surfers - there usually isn't snow around them. Pulling on a sled could be tough depending on the distance, but if you have a snowmobile, and if you can wrap him like a burrito and shield his face with a tarp or blanket, it could be a quick way to get him around.
Good luck this winter!