Nigel and Lakevia Crawford filed a malpractice and wrongful death lawsuit.
They say Nigel Jr. died as a result of a doctor's failure to diagnose and treat a disorder that causes blood clots. The lawsuit says the mother had APS and her doctor failed to take that into account when treating her pregnancy.
The lawsuit says Nigel Jr. was born prematurely in 2010 with clots in his lungs and had many medical problems before this death.
A spokesperson says Northwestern does not comment on pending litigation.