I want to ask what if we appointment a person who has never done hajj nor will ever be able to perform because of his financial condition, can we appoint him for our proxy hajj while he will intend hajj for our deceased parents as he doesn't have due obligatory hajj upon him? Can a financially who hasn't done hajj be a proxy agent for hajj?

It is completely permissible for the proxy to not have done Hajj before. He can go as a proxy and it would be valid. Yes later in life if he becomes financially capable he must go for himself.