1. b/f on flop rest of the hand kinda depends.

2. raise

3. 3bet usually

4. 3bet.
another thing though with his 20/12 range is look if he is positionally aware. like if he has a lot higher attempt to steal he is positionally aware so his utg raise is going to be a lot tighter than if his attempt to steal is only like 11 then he is probably opening 11% from all over the table so its not as tight of an utg range. i would 3bet either way though.