First of all you are not the one who's having problem with that person. If you want to report him in the police station your pregnant friend should come back to Qatar she have to bring the baby if she delivered already. Then she have to report him and to til the police she was having an affaire with him. Then they will do medical examination and DNA test to prove if this child is belong to him or not.
If he was the father then they have two choices eather marry her or both will be put in jail for illegal affair.
If he is not the father then your friend only will be in jail.