Can {Purphoros, god of the forge} be used as a commander in a commander deck?
I dont see why not. It is technically a creature card.
Yes
RESOLVED
K thanks
What happens if he gets exiled remove from the game does he still go to command zone?
Yes. Youre trying to confuse yourself. Just because he is an enchantment doesnt mean the universe is fallig apart any more than having {Sharuum the Hegemon} as an artifact breaks reality. All the same rules apply.