dear, as i can understand here, the major compaliant your mother is facing right now is that of insomina. insomnia is a symptom that can have a varied etiology. A unless one doesnt get to the etiology the treatment of the condition is mainly symotomatic. considering the age of your mother, and the medical condition that she is having, it is quite possible that she is having an underlying depressive picture. In such case we ll need to treat the depressive factor first second common ccause could be an anxiety disoder, esp commmon in the patients of heart disease. here an addiction or changing of anti hypertensive drugs can work well. A third cause could be an medication assciated casue, as she is on multiple medications already, For this she need to consult the treating clinician and request for change in medications. why this insomnia needs to be corrected, because it can have a very dreadful effect on the mental as well as physical health, as sleep is very very essential. remember disturbed sleep is the first indication of some mental problem. therefore a psychiatric consultaion will help for sure. hope i was able to guide you through your problem.thanks