1. If he pays off his girl friend in preference to paying his other creditors (which he would be doing if he does what you describe) and goes bankrupt within 2 years of doing it the OR could attempt to undo the transaction by demanding the money back from the girl friend.
2. Also, if he gets a loan to pay her off knowing that he won't be able to pay it back and intends to go bankrupt this is a bankruptcy offence, is fraudulent and could result in prosecution.
3. If he goes bankrupt the debt to his girl friend has to be dealt with in exactly the same way as all his other debts. He cannot omit it from the bankruptcy and is prohibited from paying her anything while bankrupt.
4. He does not have to be unemployed to go bankrupt.
5. It is not possible to generalise about the effect of UK bankruptcy on finances abroad. It probably depends partly on the bank etc. used and how close their links are to UK banks etc.