Friends mariage of convenience

[concerned friend]

I am helping my friend who is at his wits end and doesnt know what to do.He got married to a south american girl in 2002 in northern Ireland to help her gain residence here in the south .Both were living in the republic and lied that they were resident in the north at the time.She was also illegal and paid him for this $3000.

My friend greatly regrets this now ,especially when there is so many genuine couples out there.

Three years to the day later, the girl walked out on him,making it fairly obvious that she was just there for the 3 year marriage and was able to get whatever visa applies.Both of them signed for a mortgage on a house.She demanded a seperation and money which he carried out because of his fear of trouble from the authorities if he told them the truth and to keep the peace with his ex .She signed over her half of the house and he remortgaged the house in his own name.He now owns it 100 %


They are seperated 4 years next march which makes him eligible for a divorce but recently his ex has been in contact to say that she wants more money .He told her that enough was enough , he was going to contact immigration.She warned him tht if he did , she would deny everything and take him to the cleaners.

She will be resident in ireland 7 years next march,3 years married and 4 years seperated.

1 Should my friend contact the authorities?

2 Can this marriage be declared void ? Should he have signed and agreed to a legal sepeartion ?

3 What are the consequences for both of them if he does?

4 How is she able to stay in the country 4 years after the marriage finished if they were not together.

Hope someone can help him with this mess!