Dear zainab I am very sorry for your huge loss.as you have described your mother was diabetic and hypertensive.you have not mentioned what treatment she was taking at that time.was there any diagnosed cardiac illness also or not.i would like to inform you that most probably she developed acute massive myocardial infarction or ventricular tachycardia and ventricular fibrillation these are abnormal rhythm from heart and are the cause of sudden death..diabetic patients are especially prone to have this type of arrhythmia . Usually most patients develop severe pain when have heart attack . But in diabetics massive heart attack may present with only sweating and extreme weakness and collapse . Hope this will help.