All the time since college is expected to be accounted for. There isn't a good way to deal with unaccounted time - in the adcoms eyes you shouldn't have any gaps you weren't doing something worth talking about. Hopefully you did something semi-productive during that interval. Volunteering, a cool hobby, odd jobs, research, taking classes. Taking care of family is understandable but sadly won't play as well as someone who did that plus accomplished something else as well. Saying you have nothing on the resume due to unemployment for X years is going to look bad.