I had mad Ondolemar a follower at some point and put him in Castle Volkihar to live. Something went wrong and he started fighting with everyone as though he was an enemy. So I took him outside and killed him. As he lay dead I don't remember if I disabled him as to keep my yard clean but recently I wanted to see if I could rehabilitate him. So when I tried to console Command him, you would see him flash in and appear for like a millisecond but would not remain. What is going own? If he can't be consoled commanded because I disabled him How can I restore him?
You broke your game, dont use console commands until you really have to, Dont kill essential NPCs. NEVER!! You wont appreciate that solution, but just start a new game without using the console.
Thats all i have to say.