Thanks for the question. The DatabaseConnector package uses JDBC, and Kerberos uses different JDBC authentication parameters to the regular username/password authentication. So DatabaseConnector won't work as it stands with Kerberos and Impala since it doesn't know about these parameters.
Do you have a Kerberos Impala environment you are trying to use or is this more hypothetical? It's generally worth getting things working with Impala standard authentication (at least in a test environment) before enabling Kerberos.