@davis_mc , your statement that he has opened a bank account implies that he has a tax id ( probably SSN ). In such a case, I would not look back but look at the future and how to bring him into compliance. Thus I would suggest filing MFJ and with all its benefits. This will have him contributing to SECA / FICA and this would be good for when they retire.
There are also other reasons for brining the person into compliance.
That is my view
pk
