As GK said, there's some ambiguity in the law as to what constitutes "immediate family". The Prop Lease defines it but only with respect to SHs.

V - A friend of mine on a Queens coop board went to court over a super's sister who lived with him (16 months after she moved in.) The court said the super had a wife/two kids living with him and the sister wasn't "immediate family" and had to leave. The super's attorney appealed on the basis that the coop knew about her for 16 months and had no issues with her. The super's lawyer also questioned the court on whether the sister WOULD be considerd "immediate family" if the super was single and had no wife/kids. The ruling was overturned and the sister was allowed to stay.

Coops should have a written agreement with supers to spell out job responsibilities, benefits, etc. and all terms of employment - including who can live with him. It will save a lot of time, trouble, aggravation and money down the road if you outline everything clearly up front and in writing.