T.
Here are a couple of ideas:
1. Put him in his crib with a crib tent on it. It zips open from the outside. He shouldn't be able to get it open. You will know he is safe. He might cry for the first night or two but stick it out. Tell him he is going camping in his new tent and make a game of it. He needs to sleep in his own bed in his own room.
2. No more sleeping with you, Dad, or Grandma. If he knows this is an option, he will fuss until he gets what he wants. Consistency is key!!
3. Put rails on the full size bed to make it harder for him to get out. Every time he gets up, escort him back to bed without saying a word. It may take awhile but he will get the idea.
4. Make sure his dresser and any other big pieces of furniture are securely attached to the wall so they can't fall over on him.
Good luck!!