Considering the fact that she is diabetic,hypertension
seems to be the most likely reason for her nose bleed but there could be other reasons for bleeding from nose which needs evaluation.
Other causes could be..
Bleeding due to associated consumption of blood thinning drugs like aspirin
Presence of some liver
Rarely due to presence of some abnormal blood vessels or even cancer in nose.
Since treatment would depend upon the cause,she requires a consultation with doctor along with necessary investigations.