Why did Mary stop attending college in The Other Wes Moore?

The other Wes Moore's mother, Mary, is a highly intelligent woman. Despite falling pregnant at the tender age of 16, she remains determined to become the first person in her family to get an education. So, after completing her Associate's Degree at Community College, she enrolls at the prestigious Johns Hopkins University. She works part time to put herself through college while at the same time supporting her family.
Unfortunately, Mary's Pell Grant—which is a Federal government subsidy—is terminated due to government cut backs. This forces Mary to drop out of college, destroying her hopes and dreams of getting a good education once and for all. What this episode highlights is the enormous inequalities in the provision of higher education in the United States. What should be a way out of poverty is so often denied to those who need it the most.