C.O.
A.:
Go to the gym with him. Don't just ASK him to go. GO WITH HIM! Find a gym that has child care services so there is no excuse.
Go for a walk with him. Do things outdoors as a family to promote overall health.
Start making his lunches for work so they are healthier.
Fix healthier meals at home - less fried foods, less white carbs...after dinner go for a walk around the block - let the dishes set. They will be fine...they can be done when you get back.
Go on bike rides together...you are in MN - go skiing together...canoeing...get the whole family moving and exercising...show him how much you love him HEALTHY!!!
Good luck!