Husband's ADHD has become dangerous

My un-medicated ADHD husband has common ADHD problems like closing doors and cabinets, but it has come to a point of being potentially deadly to us and our pets. He has left the stove burner on multiple times and walked away without realizing it was still on. He even went to work with the stove on and I'm thankful I had a house to come home to. My husband has left the fence unlatched so that the dogs have had free roam of our neighborhood and I'm afraid our big dogs will be shot for being scary. And yesterday was the last straw. I went to leave for work and happened to open his car door to grab something and one of our cats jumped out. He was apparently locked in the car all night and had I not found him, probably would have died from heat exhaustion before I made it home from work. I'm at a total loss about what to do. I need suggestions on how to help him remember things like closing doors, locking gates, turning off the stove, and generally checking behind himself for our animals to make sure they aren't being put in danger.