To be honest, while a lot of it was because he got cancer, he had already been quite popular at the beginning of his term. Overall, it was mostly a reaction to the Rain Tax era of O'Malley, and the weak candidacy of Anthony Brown.
I believe that your numbers are incorrect for the debt. The state has a debt of $52 billion, and it's actually increased. If you meant to say deficit, that is also incorrect. The state is running a deficit of about $11 billion.
I teally hope something finally happens with cancer.